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Merovingian
28th-May-2006, 08:50 PM
There have been many threads on how much tension is important in leading, but something that has plagued me since my first day in class, doing the first move, has been .. the right hand.

In the first few weeks of my classes a few ladies were annoyed about how some of the leaders push 'em too hard or pull back too much (these ladies were not beginners), which has lead me to be gentle when leading the moves; and I have been leading a number of beginners and intermediate moves with varying degree of success, but sometimes dancing with some of the experienced followers I seem to get the comment "don't be so gentle with me" or "you can hold tighter".

Now that's embarassing :blush:

But the question here is when does a push become a shove?

When trying something like a sway, how much of a hold is necessary and how much is acceptable?

When trying something like the catapult / crossed return / first move surprise i.e. where the leaders are supposed to relocate the followers, how much of a pull is acceptable? (is it really an attempt at physical relocation, or just an indication and some help :confused: )

erm .. help?

Ghost
28th-May-2006, 09:36 PM
But the question here is when does a push become a shove?
erm .. help?
It depends (sorry :blush: ). The following are all generalities based on my limited experience.

I've been described as "like dancing with feathers". Not everyone I dance with feels this is a good thing.

In general, lady taxi dancers seem to develop more tension in their arms ( I believe as a defence against beginner leads yanking them around :blush: ). As such they prefer a stronger lead (note prefer - they can still follow a soft lead :worthy: )

Speed seems to be the other factor. The faster dancers prefer a stronger lead, which again if you're really moving is not unreasonable. Slower dancers prefer a softer lead

Playfull dancers seem to work best with a soft lead so they have more space to interpret the music -:cool:

The more intricate the moves the softer the lead too - when I lead Jango moves it's a strange blend of a very strong frame, but a very soft lead (Kind of a yin-yang thing)

Ultimately do what you want and listen to feedback. If you can remember who likes a stronger lead, then it's up to you if you want to provide it. It's probably worth considering that as long as your moves are fluid and the elbows don't extend fully, you can use a lot of force in your lead without yanking (Kinda scary actually - you can lead with far more force than it'll take to pop a joint :tears: )

Be Well,
Christopher

El Salsero Gringo
28th-May-2006, 10:16 PM
Here's a suggestion: designers of theme-park rides measure four parameters along each axis - velocity, acceleration, jolt, and jounce - each being the derivative w.r.t. time of the previous one. An exciting ride needs a sufficient quantity of both jolt and jounce at various points in time.

In respect of the force you need to apply to an object of fixed mass, a constant force provides a constant acceleration, a force that increases linearly with time will provide a constant jolt, and a force that increases quadratically in time gives a constant jounce.

Since (I suppose) a nice dance is probably diametrically opposed in feel to a ride at a theme-park, how about arranging the force exerted upon the follower through the lead points to minimise the a) jounce and b) jolt experienced by the follower while still moving the follower's arm/hip/[insert lead point] from one position of the move to the next consistent with remaining in time with the music.

I also remember a research project that sought to establish that the body controlled its own motion in dynamic reaching tasks (like moving your hand to intercept a moving object) in such a way as to minimize the fourth time derivative of position (that would be correlate with the jounce as defined above). Supposing that having your body lead in a simlar way to the way it would move itself would be comfortable, minimizing the jounce seems like a good idea.

I should add that I look forward to David Franklin telling me I'm talking a complete load of *******s.

Ghost
28th-May-2006, 10:22 PM
Here's a suggestion: designers of theme-park rides measure four parameters along each axis - velocity, acceleration, jolt, and jounce - each being the derivative w.r.t. time of the previous one. An exciting ride needs a sufficient quantity of both jolt and jounce at various points in time.

(snip)
Since (I suppose) a nice dance is probably diametrically opposed in feel to a ride at a theme-park,
What about an exciting dance? (This is actually intended as a serious question - I'm thinking more of velocity and acceleration, but jolts could be like yo-yo block direction changes? Jounces would be drops maybe?) - could you then increase the amount of force used?

Be Well,
Christopher

David Franklin
28th-May-2006, 10:51 PM
I should add that I look forward to David Franklin telling me I'm talking a complete load of *******s.Sorry to dissapoint, but I pretty much agree with everything you wrote. (I'd not heard about the research on human movement, but it wouldn't particularly surprise me).

The only thing I'd add is that as a practical point when dancing, if you use a lot of force, you want to make sure your partner is expecting it. This is all kind of implicit in the jolt/jounce discussion - if you minimise the jolt, you don't change the acceleration (force) suddenly, so your partner knows what to expect. But your partner may also get advance warning from your grip, or from a change in the music, or even a verbal lead.


What about an exciting dance? (This is actually intended as a serious question - I'm thinking more of velocity and acceleration, but jolts could be like yo-yo block direction changes? Jounces would be drops maybe?) - could you then increase the amount of force used?As ESG says, the amount of force corresponds to the amount of acceleration - not the jolt or jounce. In simpler terms, using a lot of force is not necessarily a bad thing, but suddenly using a lot of force almost certainly is.

As for doing dips and drops, I've come to the conclusion that you should do them smoothly if you want to avoid injuries. You can do sharp snappy drops, but you and your partner will be taking a lot of the strain on your joints and tendons, which isn't great for long term health. Fine if it's your competition partner and you agree to do the moves like that, but in general freestyle it's not a good plan.

DavidB
28th-May-2006, 11:01 PM
For normal vertical dancing (ie no drops, leans or aerials) then the force comes from the lady's legs, not the mans arms.

Any lady who says you need to be stronger should stop being lazy and move herself. Laziness is the man's job.

El Salsero Gringo
28th-May-2006, 11:09 PM
For normal vertical dancing (ie no drops, leans or aerials) then the force comes from the lady's legs, not the mans arms.

Any lady who says you need to be stronger should stop being lazy and move herself. Laziness is the man's job.Not always. Aside from the fact that I think you're confusing force with energy ("the energy comes from the lady's legs..."), how would you lead the lady into a triple spin on the spot without more force than you'd use for a single spin? How do you indicate that you want to double-time a move except to lead it faster - which you can only do with extra force?

ducasi
28th-May-2006, 11:43 PM
In the first few weeks of my classes ... I think this is the crucial line in Merovingian's post... In classes moves are often done in a start-stop way, so there can be lots of pushing and shoving that shouldn't happen in dancing for real as all the steps in the moves are smoothed out.

Ghost
28th-May-2006, 11:52 PM
how would you lead the lady into a triple spin on the spot without more force than you'd use for a single spin?
I've learnt the lady will do what she wants. Val Forsey admits to having blown off Dave's extra energy when he wanted her to do a triple in freestyle and instead just performed a nice sloooooooow single turn :devil: I never quite know how many spins the lady will do - I see it as a style point for them to decide. I may offer enough energy for a triple, but what they do with it is up to them.


How do you indicate that you want to double-time a move except to lead it faster - which you can only do with extra force?
This sounds right, but I know it's wrong. Provided the lady is following well, the amount of force between you is (pretty much) constant. I can (and have) run across a room with a woman* with a very light lead (empty dance floor - had to be done :whistle: ). Halo polishing is light, no matter how fast I do it. :innocent:

Be Well,
Christopher

EDIT * forgot that rather important detail

El Salsero Gringo
29th-May-2006, 12:17 AM
I've learnt the lady will do what she wants.Most of the time, the lady *wants* to do what I'm trying to lead*, otherwise there's not a lot of point in dancing with me!
This sounds right, but I know it's wrong.Not much to discuss, then, is there?

As regards the amount of force you put in to a lead - it's not just up to you alone, for you can only ever put in as much as your partner puts back, otherwise your frame collapses or your hand(s) shoot off into the distance (just like when you stand, the floor only ever pushes back on your feet exactly as hard as you bear down on it - otherwise you would shoot upwards into space, or fall down through it.) A good follower will give you back exactly what you put in - that force then becomes a mode of communication between you. It's a subtle thing, really.

*Except Tessalicious, for some reason.

MartinHarper
29th-May-2006, 12:41 AM
Thanks to ESG for a very good technical post. I learned something.

The phrases I try to remember are "body lead" vs "arm lead". If you lead the girl by waving your arms around, it's very easy to give her lots of jolt and jounce without really meaning to. On the other hand, because:


the body controlls its own motion ... in such a way as to minimize the (jounce)

... it therefore follows that if your arms are leading the girl as a consequence of movement of your body, then you will naturally minimise the amount of jounce you give her. An example would be the "Ceroc Spin" - you can lead the spin by turning your body, so your arms only move as a consequence of you turning your body. This pretty much guarantees that your lead will be decent. Oh, and it's meant to look better than standing still.


When trying something like a sway, how much of a hold is necessary and how much is acceptable?

You can hold about as much as a strong hug. A strong hold can make it easier lead/follow some moves, as the girl can feel where the whole of your body is, but I wouldn't say it's necessary. Most folks like being hugged anyway, so don't be shy.

MartinHarper
29th-May-2006, 12:48 AM
I can (and have) run across a room with a woman with a very light lead

Running across the floor is constant velocity, so you don't necessarilly need any force at all to lead that, depending how much "friction" your follower has.

Gadget
29th-May-2006, 12:50 AM
... sometimes dancing with some of the experienced followers I seem to get the comment "don't be so gentle with me" or "you can hold tighter".
I would say from the information given(*) that you seem to be "loseing" your connection with your partner, then re-establishing it further down the lead when the follower has caught up with you. The problem here is not really that your lead is too light, but that it is not consistant. To the follower, it seems that the contact is hesitant and as soon as they feel some pressure, you remove it again - hence the comments.

(*...this is deduction and supposition; I may be talking a load of manure)


But the question here is when does a push become a shove? When you exceed the amount of force needed to actually move your partner. Then it's a shove. The amount of resistance and pressure you give in your lead should equal what the follower is giving you in their responsiveness.

A simple test is leading them forward while you step back: try to keep the hand in exactly the same place relative to your body and gently step back; what you feel in the connection when the follower moves towards you is roughly the amount of force needed to lead them during the rest of the dance. Obviously this will change as you guide the follower through the dance, but it should be the base to work up and down from.

I have led men who have just starting to follow where I needed to bully them through the moves; move them and stop them - I have led ladies that move with the lightest flexing of my finger tips. I can dance with/lead both because I equal the force given in the connection.


When trying something like a sway, how much of a hold is necessary and how much is acceptable?Enough to move them; again, a constant lead with tension pulling your partner towards you, then leading them with the hand out to the side to start them turning,and stepping forward yourself and pushing the hand forward to finish the turn and collect them at your side.
Too much? dragging the follower through the move.
Too little? as long as the follower can follow, you should be able to air-lead this with no contact.


When trying something like the catapult / crossed return / first move surprise i.e. where the leaders are supposed to relocate the followers, how much of a pull is acceptable? (is it really an attempt at physical relocation, or just an indication and some help :confused: )
Neither - it's a guide. If you take your child's hand to have them follow you, you wouldn't pull at it and drag them along with you (normally :rolleyes: ) and you don't give a light tug and see if they move where you want to: you provide a constant pull in the right direction.

If you are moving the follower accross the floor (or swapping places), you need the same force as if you were leading them on the spot, the only difference is that you are moving more. How much force dose it take to get a follower to take a step forward at the second count? Why should it take any more to lead them to take another step? or more?

Spins & turns; I have danced with ladies that can spin until they bore a hole in the ground - I'm learning that primaraly I need to give them a stable platform to push off of; if they want to do multiples, they will push off harder. If I push, I will most likley send them off balance - they are pushing off me and I am pushing off them; the force I give is doubled when the follower gets it.
Again, I have found that a constant lead can dictate the speed of the turn rather than abrupt 'shove' that just says "Spin. Now.".

DavidB
29th-May-2006, 01:00 AM
Not always. Aside from the fact that I think you're confusing force with energy ("the energy comes from the lady's legs..."), how would you lead the lady into a triple spin on the spot without more force than you'd use for a single spin? How do you indicate that you want to double-time a move except to lead it faster - which you can only do with extra force?If the energy comes from the legs, then where does the force come from?

I think you are confusing leading with judo. I don't move the lady - I just suggest where she should go. The energy I'm supplying is only enough to move the lady's hand, not her body. It is her job to move everything else.

I don't lead a double or triple free spin. I lead a free spin and let her decide how many times to go round. She might push off my hand harder, and I might have to work harder to keep my hand still, but that is as a result of her following, not me leading.

Most 'double time' moves I do just omit a movement from the 'standard' move. The 'double time' is an illusion, and I lead with the same force - just a different direction.

Even leading a return with a double spin in 1 count is more about timing than force. You don't have to lead harder - just lead the first turn sooner.

Clive Long
29th-May-2006, 01:11 AM
I've learnt the lady will do what she wants. Val Forsey admits to having blown off Dave's extra energy ....


Would you you care to rephrase that? Or at least point me in Val Forsey's direction?

Wodger

timbp
29th-May-2006, 06:57 AM
Next time you catch a bus, stand up. Cup your hand around a pole -- no thumbs, no gripping, keep your arm as relaxed as possible while maintaing your frame -- and feel the compression and resistance as you maintain your position while the bus moves.

Do it on a few buses, so you can experience the difference between the driver who approaches the lights at full speed then slams on the brakes, then slams down the accelerator as soon as the lights go green, compared with the driver who slows to a smooth stop and accelerates smoothly.

Decide which experience felt better, and try to replicate that feeling for your follower.

El Salsero Gringo
29th-May-2006, 11:26 AM
If the energy comes from the legs, then where does the force come from?You can provide a force, without providing any energy. Push hard against a wall - lots of force, but if you maintain your equilibrium - keep still - no energy transfer occurs between you and the wall. The strength of a lead doesn't determine how much energy the follower takes from it - that's up to her.
I think you are confusing leading with judo.Yes - that's it - Judango - a new tripartite fusion between Modern Jive, Tango and Martial Arts!
I don't lead a double or triple free spin.I do.
Most 'double time' moves I do just omit a movement from the 'standard' move. The 'double time' is an illusion, and I lead with the same force - just a different direction.What's your advice for changing a Columbian from single to double time without using a stronger lead?

El Salsero Gringo
29th-May-2006, 11:46 AM
I think you are confusing leading with judo.I know you were being facetious, and that you might not see a similarity with the follow-the-hand style of leading, but there's much in common between Judo and a good dance lead. Particularly for moves like a first move walk through, penguin walk, columbian, and others where the leader just needs to co-opt the follower's existing momentum into dancing the move. Heck, even the humble yo-yo has a turn-and-block.

I've been waltzed around the floor before by a man who understood how to steer my momentum and it's exhilarating and exciting. I know Ceroc moves that have the same feel for the follower too. There's no way they are going to work by "following the hand" or without the input of force and, yes, energy from me.

foxylady
29th-May-2006, 11:59 AM
I feel the need to comment that DavidB and ESG lead two completely different dances (although they are both within the bounds of MJ).

ESG leads moves that he expects me to follow, and its up to me to chosse to follow or not

DavidB leads me into a position where I can decide what I am going to do with the opportunity, usually in a certain direction, and dependent on the direction the music is taking...

I am not saying that one is better than the other, but that in talking of leading they are IMHO talking about different things.... Which is one of the reasons that there is diagreement...

David Franklin
29th-May-2006, 12:07 PM
I should add that I look forward to David Franklin telling me I'm talking a complete load of *******s.Don't worry - normal service is resumed...

You can provide a force, without providing any energy. Push hard against a wall - lots of force, but if you maintain your equilibrium - keep still - no energy transfer occurs between you and the wall. I think you'll find DavidB is quite aware of the physical equations involved...

The strength of a lead doesn't determine how much energy the follower takes from it - that's up to her.Do you really mean this? You seem to be implying that you provide all the force required for the follow's movement, and it's up to her how much to resist. Outside of a few exceptional circumstances (Judo!), this isn't what should be happening in a dance. The lead provides an indication of the required movement, and the follow moves according to that indication. In other words, you seem to be saying the follow resists and so acts as a dampener on the lead - while DavidB and I would say she is an amplifier.

If you look at, say, a whip in WCS, a follow will move maybe 3m in each direction during the move. So a 120bpm track gives 2 seconds to move 3 meters (and being at a stop at each end). That's an average acceleration of 3m/s^2. So if a follow weighs 60kg, and I'm providing all the energy, then that's an average force of ~20kg I'm applying - usually through 2 fingers. I don't think so. (Yes, I can physically do this, but I'd be very aware I'm doing so).

Or just consider trying to lead a shopping trolley loaded to 60kg. I think you'll find it rather harder to lead it through rapid movements and changes of direction that the average follower.


What's your advice for changing a Columbian from single to double time without using a stronger lead?Without getting into all the ins and outs of leading a particular move, I'll just observe that just because the lead is stronger it doesn't mean it's providing the energy. When I push harder on the accelerator of the car, it doesn't mean I'm providing the energy to make it go faster.

El Salsero Gringo
29th-May-2006, 12:26 PM
Don't worry - normal service is resumed...
I think you'll find DavidB is quite aware of the physical equations involved...Pleased to hear it
Do you really mean this?Absolutely I do. I provide a force through my/our hands. If the follower allows that hand to move towards her then a force acts through a distance and energy transfers. If she doesn't allow the hand to move - by maintaining an equal and opposite force - then the force acts through no distance and no energy transfer occurs (like the wall) - GCSE physics that I know you understand well enough too.
You seem to be implying that you provide all the force required for the follow's movement, and it's up to her how much to resist.I don't know how you come up with this interpretation of what I said, so I need go no further except to say that I agree that it's a load of rubbish.
When I push harder on the accelerator of the car, it doesn't mean I'm providing the energy to make it go faster.True. I think a better analogy (if we're talking cars) is power steering. The servo mechanism acts as a true amplifier. If it's faulty, you get no steering at all when you turn the wheel (spaghetti arms) or not enough amplification (no hydraulic pressure, perhaps). But you turn the wheel regardless, and it's up the mechanism itself as to how much energy you have to put in and how much it provides.

El Salsero Gringo
29th-May-2006, 12:41 PM
Do you really mean this? You seem to be implying that you provide all the force required for the follow's movement, and it's up to her how much to resist.Look, isuppose I lead a step back by pushing the lady away with the back of my hand. She reacts against me by providing an equal force in her arm muscle which in turn is sufficient to generate the backwards acceleration of the rest of her body (the step back) before it brakes against the friction of the rear foot landing on the floor. Our hands stay perfectly still so no energy is transferred between them. But it's nonsense to ask "who" provides the force - we both do.
If you look at, say, a whip in WCSLeading a whip as far as I can tell uses the same kind of technique to leverage a lady's momentum to change her direction (energetically speaking, for free) without changing her speed (energetically costly) that Judo uses to throw someone.

If I want to dance with a shopping trolley, I'll push it up to speed (hard), then I can swing it about in arcs (just brake one of the wheels) or make it spin (very easy).

David Franklin
29th-May-2006, 12:45 PM
I don't know how you come up with this interpretation of what I said, so I need go no further except to say that I agree that it's a load of rubbish.Basically because you seem to be disagreeing with DavidB's comment that the force/energy comes from the lady's legs.

Pretty much every other part of the argument comes from the consequences of that. You've given other examples, analogies etc., but none of them are really compatible with what you disagreed with initially. (I think the most obvious problem is that if the force doesn't come from the lady's legs, you would be able to lead it the same way if she were in a wheelchair/wearing frictionless soles etc. And you can't).


And I don't see why you think there's a significant distinction here - she supplies force that is used to change her momentum and hence her kinetic energy. We can play all kinds of games about what what the exact integrals over time etc. but it's all the same thing really.

Gojive
29th-May-2006, 12:47 PM
If I want to dance with a shopping trolley, I'll push it up to speed (hard), then I can swing it about in arcs (just brake one of the wheels) or make it spin (very easy).

I can lead a basket quite well :)

Sorry - couldn't 'resist'....I think I'd better checkout of this thread now...:blush:

El Salsero Gringo
29th-May-2006, 12:59 PM
Basically because you seem to be disagreeing with DavidB's comment that the force/energy
comes from the lady's legs.for a simple step back, most of the force does come through the hands. Try leading yourself into a step back with your hand against the wall - it's very easy. Most of the backwards push comes through your arm. You can do it standing on one foot for instance - at least until you have to put the back foot down to brake you.


And I don't see why you think there's a significant distinction here.The distinction is crucial, because providing the "push" is not the same as "doing the work". You can provide more or less push, but the follower is still moving themselves.

TheTramp
29th-May-2006, 01:12 PM
But the question here is when does a push become a shove?

Are you regretting this question yet?

It all seemed soooo innocent. As a newcomer, you just didn't know what to expect.

Whatever you do, please don't get onto such threads as:

"Should the man actually move his feet when leading"
"What are acceptable ethics in opening up your own dance class"

And definitely not:

"Should smoking be allowed near the dance floor"

(Just a mild warning!)

:flower:

David Franklin
29th-May-2006, 01:17 PM
For normal vertical dancing (ie no drops, leans or aerials) then the force comes from the lady's legs, not the mans arms.

Not always.

providing the "push" is not the same as "doing the work". You can provide more or less push, but the follower is still moving themselves.
This is now completely nonsensical to me. I think I can make sense of it by some very convoluted arguments about what you count as push, force, etc., but I don't see the point.

As far as the whip is concerned, a WCS whip does involve dissipation of energy (as it's slotted). But that is beside the point - the force required to change the momentum is significant even in a circular whip. And just because force is applied in a direction orthogonal to movement and therefore doesn't cause energy transfer doesn't mean it won't be felt. Our 'signature move' is pretty much a textbook example of this - about 100kg of tension in order to spin the follow about a fixed point. And it feels brutal, to be honest.

El Salsero Gringo
29th-May-2006, 01:20 PM
... but I don't see the point.That just about wraps it up then.

Ghost
29th-May-2006, 01:27 PM
ESG - a few questions?

Do you know the four corner drop from aikido?

Would it be fair to say that the amount of force in your lead varies depending upon what you want to do?

Would it be fair to say that in some instances once you've got the lady up to speed, you're then actually using very light adjustments?

Would it be fair to say that the overal force between you is very small

Would it be fair to say that the lady's balance and momentum is very important in your style of dance - you're not so much physically manhandling her as slightly disrupting her balance in order to cause her to move / keep moving / change direction (hence the four corner drop question)?

I like Foxy Lady's answer. Different ways of approaching leading. It sounds like the ladies who want a firmer lead prefer your (ESG's) approach

(As always I could be wrong)
:cheers:
Christopher

David Franklin
29th-May-2006, 01:37 PM
I like Foxy Lady's answer. Different ways of approaching leading. It sounds like the ladies who want a firmer lead prefer your (ESG's) approachHave to disagree here, on the basis that the argument is more about ESG's analysis than his approach. In other words, I believe that even with a very firm lead, the follow is providing the vast majority of the energy. (And I think tend towards the firmer end of the leading spectrum myself).

As far as shopping trolley discussions go, I've suddenly remembered a trip to B&Q with Will, where we had a trolley loaded to approximately 100kg. And it took both of us to manouveur it and we certainly couldn't change direction quickly. Whereas I've lead ladies that heavy using only a couple of fingers.

Ghost
29th-May-2006, 01:45 PM
Have to disagree here, on the basis that the argument is more about ESG's analysis than his approach.
(Snip gOod stuff)

If I had any sense I'd wait for ESG's reply but as I'm going out soon anyway.....

His push against a wall example only works because of balance. Try this. Stand facing the wall a foot away and push off with one outstretched arm. You should fall back easily. Now face sideways to the wall and repeat. You won't move. So technically it's gravity that's supplying the energy. Which comes through your legs - which goes back to what DavidB said in the first place. No energy in the lady's legs and she'll just collapse.

But I might have misunderstood :blush:

Be Well,
Christopher

MartinHarper
29th-May-2006, 03:16 PM
Kevin + Carla, Bei Mir Bist Du Schoen, video's been linked before:
http://video.google.com/videoplay?docid=3804233447881861652&q=kevin+carla+lindy

There's a nice little move that's done at both 1m10 and 2m50, which seems to be a decent illustration of ESG's point about redirecting momentum. One thing I noticed is that Carla is controlling her own moment of inertia in order to make that redirection very easy. By contrast, a loaded shopping trolley has a large and fixed moment of inertia, and so is harder to dance with.

Saxylady
29th-May-2006, 03:44 PM
By contrast, a loaded shopping trolley ...is harder to dance with.

than all ladies - or just Carla??

David Franklin
29th-May-2006, 04:36 PM
Kevin + Carla, Bei Mir Bist Du Schoen, video's been linked before:
http://video.google.com/videoplay?docid=3804233447881861652&q=kevin+carla+lindy

There's a nice little move that's done at both 1m10 and 2m50
I'm having lots of trouble with the google player, so I can only get about 1 second of play at a time, but the two moves I'm seeing at 1m10 and 2m50 aren't terribly similar, so I can't really see what you mean. As a general comment, I think Lindy isn't a great dance to take examples from - there are many Lindy scenarios where the lead does have to provide significant force, while such scenarios are exceedingly rare in MJ or WCS outside of leveraged moves. (The other exception I find in MJ is that involved in rapid 'paired turns' like pivot turns or penguin walks).

which seems to be a decent illustration of ESG's point about redirecting momentum.
There's nothing "magic" about redirecting momentum. In other words, you can't say "it would be exceedingly painful to apply enough force to stop someone moving at 10m/s in one direction and send her back the same way in 2 beats, but because I just redirected her momentum it's OK". You cannot redirect momentum without applying a force. It's almost a definition: force = rate of change of momentum. You may do no work in applying that force (as is the case in an idealised Lindy whip), but that's a different question. I suspect you actually apply a higher average force doing a Lindy type whip than a WCS whip (in the case of an idealised Lindy whip I think the average force is PI/2 times that in an idealised WCS one). As for redirection being easy, as I said before, we do possibly the "ultimate" momentum redirection move (continuous floorsweep), and the tension required is about 100kg!


One thing I noticed is that Carla is controlling her own moment of inertia in order to make that redirection very easy. By contrast, a loaded shopping trolley has a large and fixed moment of inertia, and so is harder to dance with.It's hard to know what you're talking about given I can't identify the move reliably, but I would be surprised if the moment of inertia of Carla (as opposed to the Kevin/Carla system) was significant on a whip-like move (as opposed to a spin).

LMC
29th-May-2006, 05:27 PM
:what: @ technical stuff

I know very well that my following is lighter if I've been dancing with more 'advanced' dancers, and tends to be a bit "heavy" if I'm just off taxi duty.

For the first move - I personally prefer more of a 'pull' on the hip than a 'push' with the hand (whether I'm following or leading a first move). Other followers may well differ.

For a sway - IMO, the lead needs to be fairly 'firm' for this, to make sure that the follower actually twists in - otherwise they will just step forward.

For spinning - I'll spin how many times I damn well want to*, however much 'strength' has been put into the lead.

*usually once. Spinning is not my strong point :blush:

I expect matching tension has already been mentioned somewhere in amongst all the PhD stuff in this thread that has gone straight over my head. In theory, the follower should match the leader's tension. In practice, if the lead is *too* strong then this gets silly (and painful!). So, when faced with too firm a lead, I tend to try reducing my tension first - which frequently works by getting the leader to match me (if it don't work, then I ask them to be more gentle with me!).

To any halfway decent follower (even to those who, like me, are still aspiring to that level) clarity, confidence and direction of the lead should be far more important than its physical strength. Ditto 'flow' (what timbp said) - stop/start is far more difficult (and potentially annoying, if not painful) to follow than a smooth lead. "Noise" in the form of a bouncy hand makes the lead far more difficult to translate, which I suspect is why (in my experience anyway) hand bouncers often tend also to be yankers...

I would agree that more 'internal' tension is needed on a double time move - I'm not sure that the lead necessarily needs to be more forceful, but then I can barely follow double time moves, let alone lead 'em :sick:

The short answer to the original question is probably that it's the same as asking how long is a piece of string...

Ghost
29th-May-2006, 05:50 PM
I know very well that my following is lighter if I've been dancing with more 'advanced' dancers, and tends to be a bit "heavy" if I'm just off taxi duty.

(snip good stuff)

I think of this like talking to someone who's just come out of a loud Rock Concert - you need to shout at them for a bit :blush: . It stops them having to keep saying "Pardon?".


For spinning - I'll spin how many times I damn well want to*, however much 'strength' has been put into the lead.
:respect:

Reflecting on this a bit more; I prefer to follow in a state of "I'm a leaf on the wind" - but that's me. If a lady wants to follow in a state of more internal tension " I am woman hear me roar!", then she needs the lead to match that in order for it to work. Maybe? :confused:

Be Well,
Christopher

Merovingian
29th-May-2006, 06:15 PM
Are you regretting this question yet?

It all seemed soooo innocent. As a newcomer, you just didn't know what to expect.

Whatever you do, please don't get onto such threads as:

"Should the man actually move his feet when leading"
"What are acceptable ethics in opening up your own dance class"

And definitely not:

"Should smoking be allowed near the dance floor"

(Just a mild warning!)

:flower:

Thanks for the warning :worthy: !

... fascinating information here actually. I think the problem with these kind of questions is that there is no straight answer, I was expecting something along the lines of what Ghost <a href="http://www.cerocscotland.com/forum/showthread.php?t=8652#2">*</A> && Gadget <a href="http://www.cerocscotland.com/forum/showthread.php?t=8652#13">*</a> mentioned, and some suggestions.

(There is just so much useful info here that I can't thank each one individually, I'm already glad that I came across this forum)

And I've filed away all this technical theory for a review about 3 months from now, when I have a better lead and more experiance :)

Though I would try and stay away from jounces ( for now :grin: )

Keith J
29th-May-2006, 06:27 PM
Good Q!, lets see if this helps...
Firstly, it possibly depends on the ladies experience and yours as a lead, and measuring the required response. Let me add 'it ain't necessarily so' that the turn out is required as many advanced ladies may steal the exit to play with 'styling'. The intent and lead is gone at that juncture.

The etiquette suggests one gives a signal, if its not followed never ever persist, (this being a no pain experience). Allow what happens to occur you may be surprised at some pleasing results and learn something as well.

LMC
29th-May-2006, 06:31 PM
It's no good... I can't resist (Trampy, your list was missing one :whistle: )

KeithJ, what do you mean by a signal?

El Salsero Gringo
29th-May-2006, 07:19 PM
If I had any sense I'd wait for ESG's reply but as I'm going out soon anyway.....

{snip}

No energy in the lady's legs and she'll just collapse.

But I might have misunderstood :blush:
You've misunderstood (or we're talking at cross purposes) what I (it maybe me alone, perhaps) mean when I say energy. There's no "energy change" involved in standing stationary on the floor - my desk does it 24/7 with no source of power - so does the building I'm sitting in, and Mount Everest too. There's biological 'energy' involved in keeping muscles tense, but that (mis)use of the word energy doesn't get you very far in analysing the physics of dance.

(by the way - David F - naughty - supplying tensions in Kg - which is a measurement of mass...)

El Salsero Gringo
29th-May-2006, 07:23 PM
Have to disagree here, on the basis that the argument is more about ESG's analysis than his approach. In other words, I believe that even with a very firm lead, the follow is providing the vast majority of the energy.I don't think it's in dispute that the follower provides the energy for her motion - at least the good ones. Once again you're confusing energy and force - and they are entirely different beasts.


There's nothing "magic" about redirecting momentum.

{snip}

You cannot redirect momentum without applying a force ... as I said before, we do possibly the "ultimate" momentum redirection move (continuous floorsweep), and the tension required is about 100kg!Then it's hard to see what we disagree on. We agree that there are moves where you do need to supply a considerable force to the follower - and it isn't just a case of follow the hand.

DavidB
29th-May-2006, 07:51 PM
We agree that there are moves where you do need to supply a considerable force to the follower - and it isn't just a case of follow the hand.
No - because the moves where considerable force is needed (aerials etc) are not lead & follow moves. The lady is no longer a follower.

Ghost
29th-May-2006, 08:10 PM
Then it's hard to see what we disagree on. We agree that there are moves where you do need to supply a considerable force to the follower - and it isn't just a case of follow the hand.

No - because the moves where considerable force is needed (aerials etc) are not lead & follow moves. The lady is no longer a follower.
(I've changed the emphasis - please correct if it's now wrong DavidB :cheers: )
ie for leading spins, double time etc, you don't need to use considerable force. You can, but you don't need to.

Going back to the Judo example, it's a misunderstanding that Judo is based on force. The old guys will throw you round at insane speeds with a lead that's much lighter than mine :worthy: They're using experience, and an insane understanding of physics, balance, momentum, rythym, timing etc - but not force. Young 'uns tend to compensate by using force. I went through a phase in Ceroc of using a stronger lead where I hadn't quite got the hang of leading parts of move - now I just flow and try and make it clearer next time. That said they're plenty of people who enjoy "forceful judo" so I accept that having a more forceful lead is a way of approaching Ceroc.

ESG am I right that you agree with everything else I wrote (prior to this anyway) apart from the legs thing?

Be Well,
Christopher

David Franklin
29th-May-2006, 09:23 PM
I don't think it's in dispute that the follower provides the energy for her motion - at least the good ones. Once again you're confusing energy and force - and they are entirely different beasts.Yes, they are different beasts, but since energy = force x distance moved I'm not entirely clear what distinction you are trying to make. Given it is perfectly possible to lead a follow without any physical contact at all, I'm puzzled where you think the force or energy comes from, if not the follower.


We agree that there are moves where you do need to supply a considerable force to the follower - and it isn't just a case of follow the hand.If you can't tell the difference between a floorsweep and a lead and follow move, perhaps you need to be a little less confident that it's me and DavidB who are confused...

El Salsero Gringo
29th-May-2006, 10:33 PM
No - because the moves where considerable force is needed (aerials etc) are not lead & follow moves. The lady is no longer a follower.I don't follow the distinction; are you saying that a whip isn't a lead-and-follow move?
ESG am I right that you agree with everything else I wrote (prior to this anyway) apart from the legs thing?No, I don't know the four corner drop; Yes - I think - to the rest.
Yes, they are different beasts, but since energy = force x distance moved I'm not entirely clear what distinction you are trying to make.The distinction, for instance, that allows me to point out that you can apply a force to the follower without supplying him or her with energy to do the move.
Given it is perfectly possible to lead a follow without any physical contact at all, I'm puzzled where you think the force or energy comes from, if not the follower.I thought I had been pretty clear, but apparently not; so for the fourth (fifth?) time - force can come from the leader (in certain moves) whereas the energy tends not to, at least with a better follower.

Ghost
29th-May-2006, 10:41 PM
No, I don't know the four corner drop; Yes - I think - to the rest.
Great :cheers:


Given it is perfectly possible to lead a follow without any physical contact at all

Which leads to the obvious question - is it possible to

lead the lady into a triple spin on the spot (snip) or
double-time a move
without physical contact?

I know this can be done in the martial arts. Speed changes both from slow to fast and fast to slow, spins, throws, movement - seen 'em all done "freestyle" - I repeat - no physical contact was used.

Be Well,
Christopher

David Franklin
29th-May-2006, 10:59 PM
I don't followEnough said.

El Salsero Gringo
29th-May-2006, 11:01 PM
Is it possible to ... lead the lady into a triple spin on the spot (snip) I don't think I know anyone who can do a triple spin on the spot unassisted if they were asked (at least, not anyone I dance with regularly) so if they can't do it by themselves I can't see how I could lead them into it without physical contact.

(I suppose blowing hard to one side of them is cheating?)

DavidB
29th-May-2006, 11:01 PM
I don't follow the distinction; are you saying that a whip isn't a lead-and-follow move?The whip is indeed a lead and follow move. And it needs very little force to lead it.

El Salsero Gringo
29th-May-2006, 11:03 PM
The whip is indeed a lead and follow move. And it needs very little force to lead it.Cool. Has anyone told David Franklin?

Ghost
29th-May-2006, 11:04 PM
I don't think I know anyone who can do a triple spin on the spot unassisted if they were asked (at least, not anyone I dance with regularly) so if they can't do it by themselves I can't see how I could lead them into it without physical contact.

(I suppose blowing hard to one side of them is cheating?)
I just did one

:wink:
Christopher

MartinHarper
30th-May-2006, 02:44 AM
I'm having lots of trouble with the google player, so I can only get about 1 second of play at a time, but the two moves I'm seeing at 1m10 and 2m50 aren't terribly similar

I thought video would be clearer than a text description - ho hum. 1m11 -> 1m15, 2m51 -> 2m57. Carla is lead forward onto her right foot, blocked by a high R-R flat handhold, and spun clockwise a few times. It's not a whip-like move, no. Simple move, been taught it in both MJ and Lindy. Lindy followers tend to attack the move more, so the momentum redirection is more obvious.


I think Lindy isn't a great dance to take examples from - there are many Lindy scenarios where the lead does have to provide significant force.

I think the learning point from Lindy is that it's ok to apply moderate forces. It doesn't have to be hard work (in either a physics or a layman sense), it doesn't have to be painful, and it doesn't have to be bad dancing. I guess you could argue that it's bad modern jive, but that would require a definition of MJ, which is always going to be a struggle.

---

One way to put things into perspective: if I stand on the ball of one foot, I'm experiencing a force of ~60kg (ok, 600N) through a fairly small area. If I jump up in the air, I'm experiencing a 1g acceleration downwards. Neither of these things are painful or require heavy effort. Also, there's no contradiction between using moderate forces when dancing and maintaining a DavidB-like disdain for the expenditure of energy.

David Franklin
30th-May-2006, 08:59 AM
I thought video would be clearer than a text description - ho hum. 1m11 -> 1m15, 2m51 -> 2m57. I think it's better to give times to the second (as you have above), or if only approximate times give descriptions as well. (Plus I was looking for a whip-like move following previous discussion). Having looked at the move, I'd say the energy involved in the spin is roughly 20-25% of that involved in my whip example. So yes, it's possible for Kevin to be providing a fair proportion of the force required - but then the force isn't that great anyhow. And that's when you're taking the speeds in a performance Lindy demo and comparing to speeds I took from a beginner's teaching WCS clip.

But it's not the example I'd have chosen from Lindy or even that clip - there are some swingouts near the end that I'm sure had some fairly serious counterbalancing going on. Counterbalancing where both partners are rotating as a unit is the one "common" scenario I can think of where the lead actually supplies a force for its own sake rather than simply as a leading mechanism. (In other words where the lead has to have a certain amount of force or the move won't work). But this is far more common in Lindy than in Modern Jive, although I've given examples in MJ somewhere above.


One way to put things into perspective: if I stand on the ball of one foot, I'm experiencing a force of ~60kg (ok, 600N) through a fairly small area.But we don't (usually!) lead with the ball of the foot, and legs are far far stronger than arms. Otherwise everyone would be able to do 1-handed overhead lifts with no difficulty.


If I jump up in the air, I'm experiencing a 1g acceleration downwards. Neither of these things are painful or require heavy effort. Coming from someone who understands physics, this seems a somewhat disingenious point. Play fair, Martin.

El Salsero Gringo
30th-May-2006, 10:06 AM
When
I don't follow the distinction;is turned into

I don't followEnough said

...this seems a somewhat disingenious point. Play fair, Martin.um... which kind of fair are we looking for, here, David?

David Franklin
30th-May-2006, 10:15 AM
um... which kind of fair are we looking for, here, David?I draw a distinction between an admittedly cheap shot that was intended to be funny , and someone making a statement they (should) know isn't actually relevant to the discussion but they think will convince people who don't understand what's going on.

Or to put it another way, my reply to you could be considered rude, but unlike MartinHarper's reply, it isn't likely to actually mislead anyone.


Although I generally disapprove of quoting out of context, there was a "meta" joke going on, in that I brutally cut all your subsequent words and commented "enough said". Like all jokes, it loses something if you have to explain it.

El Salsero Gringo
30th-May-2006, 10:20 AM
I draw a distinction between an admittedly cheap shot that was intended to be funny
, and someone making a statement they (should) know isn't actually relevant to the discussion but they think will convince people who don't understand what's going on.

Or to put it another way, my reply to you could be considered rude, but unlike MartinHarper's reply, it isn't likely to actually mislead anyone.

Although I generally disapprove of quoting out of context, there was a "meta" joke going on, in that I brutally cut all your subsequent words and commented "enough said". Like all jokes, it loses something if you have to explain it.Yes, I got the 'joke' - but why did you feel the need to be 'brutal', rude, or twist the meaning of what I said at all? I do follow in Ceroc, by the way. Do you?

David Franklin
30th-May-2006, 10:55 AM
Yes, I got the 'joke' - but why did you feel the need to be 'brutal', rude, or twist the meaning of what I said at all?Actually, I hoped it might defuse the situation, or at least give a chance for the actual discussion to restart itself. (My father once told the story of working on a commercial with Kenny Everett where things were going wrong and things had got a bit heated. And then Kenny's reply at one point in the discussion was simply "C**t!". And everyone fell about laughing, and the tension was broken. I, of course, am no Kenny Everett).

When it comes to twisting, I don't think the way I quoted you was likely to cause people to misunderstand your position. I didn't put in a full stop, so there was clearly context missing, and your original post was only two posts above, after all. If that wasn't enough, my apologies.


I do follow in Ceroc, by the way. Do you?No I don't, though I have done many years ago.

MartinHarper
30th-May-2006, 10:57 AM
But we don't (usually!) lead with the ball of the foot, and legs are far far stronger than arms.

Yeah, doing a handstand or hanging from some bars is harder than just standing, and harder than I'd want to work when dancing. Even there, a handstand isn't painful - just uncomfortable.


Coming from someone who understands physics, this seems a somewhat disingenious point. Play fair, Martin.

Perhaps. My point is just that there's nothing inherent in being smoothly accelerated that needs to be unpleasant. Gravity is painless, but the sudden deceleration upon hitting the ground can sting a bit.

Lory
30th-May-2006, 11:17 AM
when does a push become a shove?


IMO there's a simple answer....When you use more force than necessary, to achieve the objective :)

David Franklin
30th-May-2006, 11:24 AM
Yeah, doing a handstand or hanging from some bars is harder than just standing, and harder than I'd want to work when dancing. Even there, a handstand isn't painful - just uncomfortable.I think it would take less than the duration of one dance for that handstand to start feeling painful, let alone the duration of an evening.

The other point is that a handstand is pretty much "it" for 90% of people. A few will manage to walk on their hands, and a very very few will be able to hold a hand-stand on one hand - and that will be a static hold. Whereas I can actively lift maybe 5x my bodyweight on one foot.

My personal experience is that I've spent many many hours in the gym, I've done cable pulls with all kinds of weight settings, I've used all manner of dumbbells, and I find even 5kg is a lot to deal with on a continual basis. Maybe you guys are all just much stronger than me. (In which case I don't want to ever hear someone complaining that aerials are all about strength again! :wink: )


Perhaps. My point is just that there's nothing inherent in being smoothly accelerated that needs to be unpleasant. Gravity is painless, but the sudden deceleration upon hitting the ground can sting a bit.Two points:

Firstly, free-fall acceleration is almost the canonical "body acted upon by gravity but feeling no force" example - it's the same situation faced by astronauts floating in space. So it's hardly surprising it's not painful.

More generally, pain or discomfort during acceleration has nothing to do with the smoothness of the acceleration - it's all to do with the forces and how they are spread. Suppose you're on roller skates. If I use my whole body to "lead" you, a 1g acceleration isn't going to be a problem. If I use a sharp object like a needle, even a twentieth of that acceleration is going to hurt, no matter how smoothly I apply it.

David Franklin
30th-May-2006, 11:25 AM
IMO there's a simple answer....When you use more force than necessary, to achieve the objective :)I think I should hate you, for making us all look stupid, but

:respect:

:love:

Ghost
30th-May-2006, 12:35 PM
IMO there's a simple answer....When you use more force than necessary, to achieve the objective :)

I think I should hate you, for making us all look stupid, but

:respect:

:love:
Out of the mouth of a babe...........

:worthy:
Christopher

MartinHarper
30th-May-2006, 12:44 PM
IMO there's a simple answer....When you use more force than necessary, to achieve the objective :)

I can lead a Ceroc spin purely visually on most followers to most songs, so the minimum necessary force there is no force at all. Does that mean that if I lead it normally then I'm shoving my partner around?

spindr
30th-May-2006, 12:54 PM
IMO there's a simple answer....When you use more force than necessary, to achieve the objective :)
Hmmm, that's fine as long as the objective is to have an enjoyable dance with your partner -- not so good if the objective is to complete a lesser-spotted-twizzle-fandango to hit a break.

Followers *should* mirror the "connection" from their leaders -- but *leaders* should also mirror the "connection". A lead can have a widely varying response from a follower with a superb connection to that of a follower with a less robust frame, spaghetti arms, etc. A safe lead on a robust frame might well jolt a loose one badly.

Physics is great -- and will precisely explain the situation if you are trying to move an inanimate object without a mind of its own. However, lead and follow should be a conversation -- with the connection (physical / visual / etc.) between partners being the "communication medium" (admitedly that communication may be "You have no choice, but to do XXXX" but that seems a tad unsporting).

So, give as much information as you can -- start early -- use both hands, arms, body, etc. to convey your request, etc.

SpinDr

Ghost
30th-May-2006, 01:24 PM
I can lead a Ceroc spin purely visually on most followers to most songs, so the minimum necessary force there is no force at all. Does that mean that if I lead it normally then I'm shoving my partner around?
Nope - it presumably means your objective has changed eg you want to be in physical contact with her. I can just sit down and give verbal instructions (Heaven help me if I ever tried this with Taz though :whistle: ), but I prefer to actually physically dance with a lady.

It's also a two way street. I get feedback from the lady through the connection eg floorcraft and play / improv.

Ok serious question in NO WAY meant to be derogatory

I do follow in Ceroc
Can you do a triple spin on your own?



Physics is great -- and will precisely explain the situation if you are trying to move an inanimate object without a mind of its own. However, lead and follow should be a conversation -- with the connection (physical / visual / etc.) between partners being the "communication medium" (admitedly that communication may be "You have no choice, but to do XXXX" but that seems a tad unsporting).
:cheers:
In fairness to Merovingian, dance as a conversation is only one way of approaching it. There are others (http://www.cerocscotland.com/forum/showthread.php?t=7828&highlight=piano). My somewhat fractured thoughts are here (http://www.cerocscotland.com/forum/showpost.php?p=206552&postcount=13)

There's other threads too

Be Well,
Christopher

El Salsero Gringo
30th-May-2006, 01:26 PM
Can you do a triple spin on your own?No. I can do a double - sometimes. But off my own bat, so to speak, when leading. I'm not very good yet at being led into spins at all.

El Salsero Gringo
30th-May-2006, 01:30 PM
Physics is great -- and will precisely explain the situation if you are trying to move an inanimate object without a mind of its own. However, lead and follow should be a conversation I don't see why it's any less useful if there are two of you. Your bodies both still obey the same universal laws that Newton worked out three hundred years ago, as long as you bear in mind that you both have muscles that apply forces.

Most problems in physics become simpler when you use the right vocabulary - mathematical or English - to describe them. That's why it's worth being very precise about the use of words like force, energy, and so on.

I think the tools of the physicist may be of much use in characterising the differences between different lead/follow ideas; if so then it should certainly be possible to work out better explanations of what makes a good lead/follow albeit that people mean different things by 'good' in this context. At the least it would help to remove some of the inevitable misunderstandings that occur when people cant see that the cause of an argument is down to different usage of the same words.

Loughborough University (among many others, no doubt) does a great deal of research into sport science, and the biomechanics of playing football, athletics, tennis etc. I'm sure some of the same tools would work in dance, if they're not already being used. Who know, it might help people to learn to dance better together.

LMC
30th-May-2006, 03:20 PM
The more I think about it the more I'm probably way off track...

It seems to me that for a "fast" move (e.g. double time Columbian, triple spins, etc) that it's the leader's and follower's internal tension which determines whether the lead will work or not, rather than the forces in operation between them. We all know that spaghetti arms make for "mushy" moves - whether of leader or of follower. To me, it's not a question of force or resistance, more of alignment (whole body moving in reaction to the "input" from the contact point of the lead) and response/connection (muscle 'readiness'). Applies to follower and leader both.

I can't comment on a whip because I'm crap with move names and am having trouble visualising exactly what a whip move is (can't play video at work, will look later). However, from a follower's POV: I need far more abdominal/core tension to effectively follow a double time move than I do for a single time one. Yes, fast moves need more energy - but it appears to me that the energy should come from within rather than from your partner.

David Franklin
30th-May-2006, 03:40 PM
Loughborough University (among many others, no doubt) does a great deal of research into sport science, and the biomechanics of playing football, athletics, tennis etc. I'm sure some of the same tools would work in dance, if they're not already being used. Who know, it might help people to learn to dance better together.The most quoted work amongst dancers is probably The Physics of Dance by Kenneth Laws, since updated as Physics and the Art of Dance. I don't have it, though I keep meaning to stick it on an Amazon order when I remember. From what I've seen it deals more with ballet-style dance rather than social lead and follow. (Though it does contain discussion of partner movements, lifts, etc.)

As far as lead-and-follow goes, Sommer Gentry has based much of her research on analysis of lead and follow in swing (largely Lindy, I believe), with particular reference to cybernetic systems for lead and follow using haptic (touch) interfaces.

A paragraph from one of her papers I found relevant to the discussion:


It is crucial to note that although the PHANToM leader is implemented as a position and velocity controller, the human follower holding the stylus is not constrained to move as the target does. The subject must actively move his hand and arm to follow the dance. This is due to the small gains kp and kv . Larger gains would not be implementable using this device, and would not be desirable in that they would not permit soft interaction. Soft interaction means that the user is presented with a haptic error signal but not physically forced through the motions; soft interaction is realized in partner dancing.

Context for this bit: basically kp and kv being small means that the actual force conveyed to the follower was very small - less than 1N and averaging maybe a 10th of that (i.e. less than an ounce)

Ghost
30th-May-2006, 03:52 PM
No. I can do a double - sometimes. But off my own bat, so to speak, when leading. I'm not very good yet at being led into spins at all.
Fair enough :worthy:

I can see why you view things the way you do. So if I was leading you, I would need to kick in extra force to get you to do the triple (Actually there are a few important exceptions -
I could lead the move so well that you'd be able to do the triple without the extra force
I could also stick to leading moves I could lead without the extra force).

So really what's being said I think is that it's a matter of skill and style. Whether you need to use the force depends upon the relative skill of the leader and follow. Whether you want to depends on the preferences and style of the Lead and Follow.

But then I've now got a headache, so maybe not :confused:

Be Well,
Christopher

David Franklin
30th-May-2006, 04:07 PM
I can't comment on a whip because I'm crap with move names and am having trouble visualising exactly what a whip move is (can't play video at work, will look later). For what it's worth I chose a whip because it's about the simplest (in terms of momentum changes) move I could think of which wasn't completely trivial. I'm less comfortable giving MJ examples because the way I was originally taught was very 'old-style Ceroc' with lots of big forceful arm leads, and the way I do it now is quite different and probably non-standard.

But instead of a whip just think about any MJ move where you travel down the slot - work out what your average acceleration must be during the move and how much force that acceleration requires. Then think about the average force you feel from the lead and decide for yourself how much it contributes to your acceleration.

El Salsero Gringo
30th-May-2006, 04:34 PM
It seems to me that for a "fast" move (e.g. double time Columbian, triple spins, etc) that it's the leader's and follower's internal tension which determines whether the lead will work or not, rather than the forces in operation between them.My opinion is that without the internal tension there's nothing to be achieved by using any force between you - it would be like trying to push a puddle of water. Leading many followers does in fact feel a lot like this. However, once that internal tension happens the forces between the dancers have something to act on and a very magical thing occurs in the dance the two of you are sharing.

El Salsero Gringo
30th-May-2006, 04:37 PM
Fair enough :worthy:

I can see why you view things the way you do. So if I was leading you, I would need to kick in extra force to get you to do the triple (Actually there are a few important exceptions -
I could lead the move so well that you'd be able to do the triple without the extra force
I could also stick to leading moves I could lead without the extra force). No - because in my case it's not a lack of angular momentum that prevents me from doing a triple spin - it's a lack of balance. Putting extra force in will simply throw me off balance sooner.

The example about how to lead a triple spin vs. a single was just this: with an expert follower who's equally at home with single or triple spins: leading the spin at one speed will result in the lady going round once in time for the next beat. If I *want* her to spin three times in the same space of time - and if she wants to cooperate with me on that - then I will lead the spin faster, and using more force (more firmly / harder / stronger) than if only intended her to spin once. What she does with the extra momentum that I'm prepared to give her is up to her, but by my pushing harder she can feel it's there if she wants it. She has the option to push back against me harder. And yes, in this case I am providing both force and energy to complete the move. Not *all* the energy - but some.

The force that I am going to apply is not an absolute amount that can be compared between followers; but other things being equal - more push = faster spin. Simple as that.

LMC
30th-May-2006, 05:35 PM
My opinion is that without the internal tension there's nothing to be achieved by using any force between you - it would be like trying to push a puddle of water. Leading many followers does in fact feel a lot like this. However, once that internal tension happens the forces between the dancers have something to act on and a very magical thing occurs in the dance the two of you are sharing.
Ezackly - but the point is that those of us who aren't as physically fit as we might be *cough* :blush: need *more* internal tension for some moves than might otherwise feel 'natural' - certainly, if a lead pulls me into a close hold for leading pivot/penguin walks then I have to consciously increase (OK improve) my abdominal tension.

On the other hand, additional impetus from a lead to get me to triple spin is just wasted - I'll still only go round once :D

Ghost
31st-May-2006, 02:18 AM
(snip - hopefully not changing the context) If I *want* her to spin three times in the same space of time - and if she wants to cooperate with me on that - then I will lead the spin faster, and using more force (more firmly / harder / stronger) than if only intended her to spin once.

(snip as above)
The force that I am going to apply is not an absolute amount that can be compared between followers; but other things being equal - more push = faster spin. Simple as that. Ok - do you need to do this is you want to lead a triple? What about musicality? If the follow's good enough to do triples, surely they're good enough to realise that a triple would suit the music better than a single? (Hmm, maybe not - guess it depends on whether you're both seeing things the same way)

(As an experiment I got someone who doesn't know Ceroc to lead me through a double spin without touching, plus she was sitting down. :worthy: )

Really where I'm going with this is that I believe DavidB is right. It can be done. But as I said on one of Gadgets thread, although it's sensible to use a screwdriver to screw in screws and a hammer to bang in nails; you can use a screwdriver to bang in nails pretty well.

It's like signalling a neckbreak - if that's what it takes, or what you or the lady prefer then :cheers:

Course having said that I played around with the whole "the force comes from the lady's legs thing" tonight
:clap::worthy::cheers:

There's a good reason he's called "The Oracle" :wink:

Be Well,
Christopher

El Salsero Gringo
31st-May-2006, 09:17 AM
Ok - do you need to do this is you want to lead a triple? What about musicality? If the follow's good enough to do triples, surely they're good enough to realise that a triple would suit the music better than a single? (Hmm, maybe not - guess it depends on whether you're both seeing things the same way)No, look, this is what you're not getting. There's no *fixed* amount of force that I need to use to lead a triple. There's no threshold that's *needed*. Some followers will no doubt do a (well, double, let's be realistic) with what feels like just a breath of air on the hand. Some don't. This is not about what suits the music better, this is not about telepathy between us, this is not about me whispering "double" in the follower's ear. If I want to lead a double, I lead faster/harder with the same follower than if want that same person to do a single. If DavidB really wants his follower to do a double spin he's going to have to lead it faster than he would lead a single. If he's going to lead it faster, he's going to have to lead it firmer, otherwise the lady's hand (or however much of her body he's 'carrying') isn't going to move faster.

The communcation is in the lead. The only communication is in the lead. The difference in the lead between a single and a double is speed and force applied.
But as I said on one of Gadgets thread, although it's sensible to use a screwdriver to screw in screws and a hammer to bang in nails; you can use a screwdriver to bang in nails pretty well. I'm not using a screwdriver to bang in nails. Trust me.

LMC
31st-May-2006, 09:22 AM
*lights blue touchpaper and stands WELL back*

Perhaps it's the same force being applied in both cases - but given that I agree that the lead needs to be "faster" for a double/triple time move (including multiple spins on one beat) I hypothesise that applying the same force over a shorter period of time means that although the *actual* amount of energy expended is the same, the apparent force is greater. The only solution is to wire ESG up with a calorimeter - all that kinetic energy he's expending has to come from somewhere - and compare the results for leading single/double/triple spins.

OK, I'm being silly

El Salsero Gringo
31st-May-2006, 09:35 AM
*lights blue touchpaper and stands WELL back*

Perhaps it's the same force being applied in both casesIf it was the same force then it would be exactly the same lead, and the follower wouldn't notice any difference. Ergo it must be a different force.
- but given that I agree that the lead needs to be "faster" for a double/triple time move (including multiple spins on one beat) I hypothesise that applying the same force over a shorter period of time means that although the *actual* amount of energy expended is the same, the apparent force is greater. The only solution is to wire ESG up with a calorimeter - all that kinetic energy he's expending has to come from somewhere - and compare the results for leading single/double/triple spins.

OK, I'm being sillyThe energy input doesn't depend on the time the force is applied for, it depends only on the distance the point of application of the force moves through (in the direction of that force).

Since energy rises as the square of velocity, doing a move twice as fast (i.e. a double spin) requires four times the energy input. Comparing the single and double spin, if the shape of the start of the move is identical in both cases, then the distance that the points of applications of force move are the same in both cases. (Those points are your leader's hand, and the leg you push off of. You can't exert a turning moment with the leg you're spinning on so that's all you've got.*) So other things being equal you need to push four times as hard to do a double spin on one beat vs. a single spin on one beat.

[*actually you can - you can alternately grip with the standing foot, wind up your torso against it, then 'jump' slightly and release the weight and friction on that same foot to spin, then land on the foot and wind up some more, jump up again etc. Ballet dancers can do it. But it doesn't change the analysis.]

LMC
31st-May-2006, 10:13 AM
Oooh, that's VERY good news. I need to lose weight, so when I'm leading I'll try to get all my followers to do double spins.

this is nearly as much fun as ringing on doorbells and running away...

El Salsero Gringo
31st-May-2006, 10:22 AM
Oooh, that's VERY good news. I need to lose weight, so when I'm leading I'll try to get all my followers to do double spins.

this is nearly as much fun as ringing on doorbells and running away...I didnt' think you were being silly before either - I'm thinking of how to include some load cells into a glove so I can measure the forces involved in different moves, as lead by different people, and the same people with different followers. I think it would be fascinating.

David Franklin
31st-May-2006, 10:23 AM
So other things being equal you need to push four times as hard to do a double spin on one beat vs. a single spin on one beat.Of course, other things aren't equal - the standard advice is you lead a double spin earlier, and my own perception is that I certainly lead it over a much longer distance. (In fact, one of the things I'm often aware of leading double spins is that I 'roll' my fingers to get that extra bit of distance where I keep connection).

I also note I'm not sure how many followers can do a genuine 1 footed double spin (quite a few can, but I don't think it's the norm). If you look at strictlywestie.com, there's been quite a long discussion about multiple 1-footed turns in WCS, and the majority opinion is that they are very much an "exceptional" move that breaks the normal rules of WCS. Primarily because the leader really does provide the torque input for the move, when this is normally verbotten.


I'm not using a screwdriver to bang in nails. Trust me.

From the rec.arts.dance FAQ
Applying physics to ballroom dancing leads to the pushy F=MA view. The proper theoretical basis of ballroom dancing is signal analysis.
If you accept the signal analysis approach, then most quantitative bets are off. For example, a force that builds up from 0 to 10N over 200ms will be percieved quite differently from one that does so over 10ms (that's why we have a jolt term, after all). And the follower is reacting to her perceptions, so...

FWIW, I think there is actually a spectrum. Aerials are pretty much pure physics. Normal moves are nearly pure signal. For me, with the people I dance with, doubles are still usually 90%+ signal. Triples and above will involve physics.

El Salsero Gringo
31st-May-2006, 10:49 AM
Of course, other things aren't equal - the standard advice is you lead a double spin earlier, and my own perception is that I certainly lead it over a much longer distance. (In fact, one of the things I'm often aware of leading double spins is that I 'roll' my fingers to get that extra bit of distance where I keep connection).If that's how you lead a double, I accept that. But by your own words there's a difference in the lead. The longer distance over which you maintain contact means you can put in more momentum without using four times the force. But you *are* putting in momentum and energy, and more for a double than a single.
I also note I'm not sure how many followers can do a genuine 1 footed double spin (quite a few can, but I don't think it's the norm). If you look at strictlywestie.com, there's been quite a long discussion about multiple 1-footed turns in WCS, and the majority opinion is that they are very much an "exceptional" move that breaks the normal rules of WCS. Primarily because the leader really does provide the torque input for the move, when this is normally verbotten.You can break any analysis you like by saying that's not how the move's done, or moving to a different dance, like WCS. I totally accept that a full analysis of every single impulse in any move is going to be impossible. That doesn't mean that thinking about the physics involved can't be useful.
From the rec.arts.dance FAQ
Applying physics to ballroom dancing leads to the pushy F=MA view. The proper theoretical basis of ballroom dancing is signal analysis.Possibly, I wouldn't know myself, or know which authority says so. But I'm not analysing ballroom. You don't lead ballroom spins with one hand, as far as I know.
If you accept the signal analysis approach, then most quantitative bets are off. For example, a force that builds up from 0 to 10N over 200ms will be percieved quite differently from one that does so over 10ms (that's why we have a jolt term, after all). And the follower is reacting to her perceptions, so...Which is what makes partner dance so interesting. If you have any references to "signal analysis" in this context, can you post them or PM me? I'd like to follow them up.

David Franklin
31st-May-2006, 11:47 AM
But you *are* putting in momentum and energy, and more for a double than a single.Something I'm unclear of, (and watch me make my own simplifying assumptions).

Suppose we have a car massing 1000kg, with a sensor on the back panel that causes the wheels to provide a horizontal traction of 999N when a force of 1N is applied to the back, so that me applying a force 1N to the back results in an acceleration of 1m/s. If I apply that 1N force for 1 second, do you consider that I have provided momentum and energy, and if so, how much momentum? Also, in a discussion of how the car gets from a to b, would you insist the momentum I provided be considered?

My answers would be "yes, one newton-second, and no". I'm sure you'd answer "yes" to the first bit, but I honestly don't know what your answers would be to the 2nd and 3rd parts.


You can break any analysis you like by saying that's not how the move's done, or moving to a different dance, like WCS. So what is someone who disagrees with you supposed to do? If you made the "classical" assumption of a spherical follower, then pretty much everything you've said would obviously be true. But I'd be inclined to point out followers aren't spherical.

In this context, I would agree with you that in a multiple turn where the follower stays on one foot, the leader very definitely provides the majority of the torque. But I very rarely see it done that way MJ, to the point where a couple doing it will stand out to my eye. I find it is difficult to lead, and I'm not the only one, as I've seen various couples working on it with varying degrees of success. There is extensive discussion of that move on another forum (albeit a WCS one) where they agree it's a "trick" move that works differently from normal moves. So I do not think it unreasonable of me to suggest it is not the usual way a follower executes the move.

Ghost
31st-May-2006, 12:18 PM
Ok I've highlighted the important bit in red. The rest is stuff I'm interested in discussing, but also kinda distracts from the point.

No, look, this is what you're not getting. Ok first of all thanks for still responding at this point :cheers: . I appreciate how frustrating it can be trying to convey a concept that someone just can't seem to grasp, particularly in text.



There's no *fixed* amount of force that I need to use to lead a triple. There's no threshold that's *needed*. Ok I need to think about this for a while


If DavidB really wants his follower to do a double spin he's going to have to lead it faster than he would lead a single. If he's going to lead it faster, he's going to have to lead it firmer. My one and only problem with this is that if I've understood him correctly, DavidB is saying that he doesn't do this. So either he's right and it's not necessary to do it the way you suggest, or he's wrong / mistaken and it is.

At this point, I would really be interested if you were to meet DavidB at a venue (you're both London based right?) and let him lead you.

Actually that leads to a simple question. FoxyLady - can DavidB lead you through triples and double-time moves without extra force?



The communcation is in the lead. The only communication is in the lead. Really tempted to discuss this further, maybe later


The difference in the lead between a single and a double is speed and force applied.I'm not using a screwdriver to bang in nails. Trust me. :wink:

Ok how about figure of 8 into Cerocspin vs Slow comb into Cerocspin. The first will more easily lead a triple without extra force because the momentum's already high, whereas the second's trickier and more naturally implies a single. (Slow comb's not the greatest example I'll admit)


I'm thinking of how to include some load cells into a glove so I can measure the forces involved in different moves, as lead by different people, and the same people with different followers. I think it would be fascinating. If you actually do this I'd be interested in the results :cheers:

Be Well,
Christopher

El Salsero Gringo
31st-May-2006, 12:34 PM
Something I'm unclear of, (and watch me make my own simplifying assumptions).

Suppose we have a car massing 1000kg, with a sensor on the back panel that causes the wheels to provide a horizontal traction of 999N when a force of 1N is applied to the back, so that me applying a force 1N to the back results in an acceleration of 1m/s. If I apply that 1N force for 1 second, do you consider that I have provided momentum and energy, and if so, how much momentum? Also, in a discussion of how the car gets from a to b, would you insist the momentum I provided be considered?I think that's pretty much how power steering works, and I think it's a fair analogy for how a follower feels. You've provided 1Ns of momentum. The car will have accelerated at 1ms^-2, and travelled (if starting from rest) a total of 0.5m. You will have provided 0.5 joules of energy. In the next second the car will travel a further 1.5m, and you will provide in that second second (sic) 1.5 J of energy (note that even though your push remains constant, the energy you need to put in to maintain the push goes up with time as the car speeds up). But I know you know all this, David.

You may be blessed with dancing always with followers who 'amplify' by a factor of 1000. I don't, not all the time. There are some people I dance with where I might judge the 'amplification' to be only 2, or 1, or less. I don't think they're unsatisfied with the way we dance together - it looks good, it feels good and they keep coming back for more.

And let me point out also that even if the force you need to apply is small, it's small linearly not quadratically (I think you know what I mean by that) - you can't "tend it to zero". You still need to quadruple it, or increase it at any rate, to make the move go faster.

Finally, the "pushing the car" analogy breaks down a bit if you consider a move where the best place for the lady to get the momentum to do the move is by bracing against your lead - do a first move for example, stopping on each beat (to minimise the 'help' she gets from stepping in) and examine what happens when you twist the lady to the side. The easiest place for her to push to turn out against is against your hand. (I know when you do the move faster, to time, smoothly, there are dynamics involved: that changes the amount of help you need to give her to twist out but not the basic point). She can still provide the energy - or you can - but you've still got to push against each other.


But I'd be inclined to point out followers aren't spherical.I agree completely. But as the joke goes, considering even the spherical horse enabled the mathematician to put his money on the right nag.
In this context, I would agree with you that in a multiple turn where the follower stays on one foot, the leader very definitely provides the majority of the torque. But I very rarely see it done that way MJ, to the point where a couple doing it will stand out to my eye. I find it is difficult to lead, and I'm not the only one, as I've seen various couples working on it with varying degrees of success. There is extensive discussion of that move on another forum (albeit a WCS one) where they agree it's a "trick" move that works differently from normal moves. So I do not think it unreasonable of me to suggest it is not the usual way a follower executes the move.Well, I didn't realise that there was a difference of opinion about double spins in MJ, I confess that I thought that they are done on one foot - which is how I do mine. Maybe I should have been more prescriptive and said "to lead a double spin on one foot" compared to "a single spin on one foot" etc.

El Salsero Gringo
31st-May-2006, 12:42 PM
Ok I need to think about this for a whileDon't think too hard - I mean only that comparatives like 'harder' or 'faster' apply only to leading singles/doubles on the same follower. One person might fly into a double with half the lead that someone else needs for a single - you can only compare the two on the same person (same floor, same shoes etc)
My one and only problem with this is that if I've understood him correctly, DavidB is saying that he doesn't do this. So either he's right and it's not necessary to do it the way you suggest, or he's wrong / mistaken and it is.Difficult to speak for others, especially for one so eloquent as David. I gather from Foxy that we lead very differently anyway. I'd like him to show me how he would lead a double spin, and I'll ask him to do just that when I next see him.

Ghost
31st-May-2006, 12:53 PM
Don't think too hard - I mean only that comparatives like 'harder' or 'faster' apply only to leading singles/doubles on the same follower. One person might fly into a double with half the lead that someone else needs for a single - you can only compare the two on the same person (same floor, same shoes etc) Ah ok I get you now - thanks. I use the preceeding move to set it up eg the figure 8 example, plus musicality, plus floorcraft, but ultimately it's their choice what to do with the energy so there's not an actual difference in the force of my lead whether I'm leading a single or a triple with the same person.


Difficult to speak for others, especially for one so eloquent as David. I gather from Foxy that we lead very differently anyway. I'd like him to show me how he would lead a double spin, and I'll ask him to do just that when I next see him. Cool. If you could either post on this thread the results (or PM me) that'd be appreciated :cheers:

Be Well,
Christopher

El Salsero Gringo
31st-May-2006, 01:01 PM
Ah ok I get you now - thanks. I use the preceeding move to set it up eg the figure 8 example, plus musicality, plus floorcraft, but ultimately it's their choice what to do with the energy so there's not an actual difference in the force of my lead whether I'm leading a single or a triple with the same person.It is indeed her choice whether to comply or not - but if there's no actual difference in the force of your lead, then you're not telling/suggesting/implying/asking/differentiating between leading single or triple - and you just aren't leading that aspect of the dance at all.


Cool. If you could either post on this thread the results (or PM me) that'd be appreciated :cheers:

Be Well,
ChristopherWill do.

Ghost
31st-May-2006, 01:09 PM
It is indeed her choice whether to comply or not - but if there's no actual difference in the force of your lead, then you're not telling/suggesting/implying/asking/differentiating between leading single or triple - and you just aren't leading that aspect of the dance at all. I am, I'm just using the other stuff I mentioned.

Put it another way - I appear to be really lucky. When I want ladies to do triples, 99% of the time they do triples. When I want them to do singles they do singles. (I suspect they're telepathic :wink: )


Will do. Thanks,
Christopher

El Salsero Gringo
31st-May-2006, 01:13 PM
Put it another way - I appear to be really lucky. When I want ladies to do triples, 99% of the time they do triples. When I want them to do singles they do singles. (I suspect they're telepathic :wink: )hehehe - isn't it amazing how much telepathy you can squeeze down a left hand to right hand hold?

Ghost
31st-May-2006, 01:14 PM
hehehe - isn't it amazing how much telepathy you can squeeze down a left hand to right hand hold?
:worthy:

David Franklin
31st-May-2006, 02:02 PM
I think that's pretty much how power steering works, and I think it's a fair analogy for how a follower feels. You've provided 1Ns of momentum. ~snip~Without wanting to belabour the point, I note that you haven't answered the last part of the question. If the car provides 99.9% of the energy, is it reasonable to say (as you did in another context):

you *are* putting in momentum and energy
My position would be it is technically true, but practically meaningless, particularly when the main starting point of this whole debate was you disagreeing with:


For normal vertical dancing (ie no drops, leans or aerials) then the force comes from the lady's legs, not the mans arms.

Any lady who says you need to be stronger should stop being lazy and move herself. Laziness is the man's job.

Only putting in 0.1% of the energy seem plenty lazy enough to me! (I grant I may not always be so lucky).


You may be blessed with dancing always with followers who 'amplify' by a factor of 1000. I don't, not all the time. There are some people I dance with where I might judge the 'amplification' to be only 2, or 1, or less. I don't think they're unsatisfied with the way we dance together - it looks good, it feels good and they keep coming back for more.I chose 1000 for convenience, I'd agree it's not terribly realistic. My belief is that for translational movements (e.g. whip, catapult), the gain is far far higher than unity, however. I would grant you that it is often lower for twist type movements; I think this is both a failure of leading (because when I get it right I can lead such twists with very little force indeed), and a reflection that it takes relatively little force to literally "force" the follower to twist, so higher gain is not required.


And let me point out also that even if the force you need to apply is small, it's small linearly not quadratically (I think you know what I mean by that) - you can't "tend it to zero". You still need to quadruple it, or increase it at any rate, to make the move go faster.Yes, but it's fairly clear at such gain levels that the change in momentum all happens "in the car", and so that is really a question of signal processing, rather than anything else. It would be perfectly possible to produce a system which took into acount the jolt, so you could actually move faster using less force, albeit applied more suddenly. And something like this actually happens in dancing - if the follow starts a leverage pose, and I slowly increase the tension, she can take advantage of that to lean away from me (-ve gain!). But a sudden increase tells her to come back towards me.


Well, I didn't realise that there was a difference of opinion about double spins in MJ, I confess that I thought that they are done on one foot - which is how I do mine. Interesting you say this. My understanding is that you do your spins by yourself, and you find it difficult to be lead to do a double spin. I didn't particularly want to confuse matters in the previous post, but my impression is most followers who do spin on one foot are actually in a similar boat. That is, they can do a double spin on one foot "on their own" - the lead may indicate, and aid balance, but he doesn't provide signficant torque. I appreciate this is something on which we may need to differ.

As a side note, in the previous post I was actually discussing multiple turns. That wasn't intended to be as a "trick" to change the subject. The reason I was talking about turns is that with a continuous multiple turn (e.g. the 30 odd turns Jordan did with Sarah van Drake in a video clip somewhere) it is very easy to say "OK, whatever initial force the girl provided, I don't believe it is making any difference at turn 10", without having to argue about the ratio of force provided by lead and follow at the start. And again, it's providing the torque without sending the follow off balance that is difficult.

As far as the prevalence of women spinning on one foot, Hannah is frequently described as one of the best spinners in MJ, and I've been at a workshop where Mick and Hannah were teaching spinning. As soon as Mick started putting any significant power in, Hannah was very definitely using two feet. And in fact, when Mick was really putting in the power, Hannah was skittering all over the place on both feet (she also did about 12 turns!) Apparently there is some research implying that it's not so much that excellent spinners have superb balance, but that they have superb ability to correct (they did things like push them off balance half way through a spin) compared with us "mortals". Having seen Hannah control those spins I can well believe it.


Men seem to spin on one foot much more often than women. I've spent a few minutes trying to find an clip with a woman spinning on one foot, and come up empty. While finding about 5 examples of men doing so. Given the amount men spin v.s. women, this is interesting. Of course, two of those clips had Kevin St Laurent and Ben Morris dancing, so...

El Salsero Gringo
31st-May-2006, 02:48 PM
Without wanting to belabour the point, I note that you haven't answered the last part of the question. If the car provides 99.9% of the energy, is it reasonable to say Yes, it is reasonable to say that given your figures, but not applicable to the case in point (dancing) because ...
I chose 1000 for convenience, I'd agree it's not terribly realistic.

Yes, but it's fairly clear at such gain levels that the change in momentum all happens "in the car", and so that is really a question of signal processing, rather than anything else. It would be perfectly possible to produce a system which took into acount the jolt, so you could actually move faster using less force, albeit applied more suddenly. And something like this actually happens in dancing - if the follow starts a leverage pose, and I slowly increase the tension, she can take advantage of that to lean away from me (-ve gain!). But a sudden increase tells her to come back towards me. What you're saying is that the follower isn't a simple force amplifier and I accept that. You can do a 'snap' lead (keep it small or it's going to be unpleasantly forceful) or all sorts of things. But to do a faster lead, other things being equal - you're going to need more force. You're moving the same mass (even if it's just her hand) but faster. Note the emphasis. I obviously don't think that lead-and-follow is pure action/reaction or else I'd have as much fun dancing with a chair. To apply your more sudden lead you have to use more force - otherwise it simply wouldn't be more sudden. Once the lady cottons on and changes the force-reaction to your lead *because* it was more sudden, then you're no longer comparing like with like, and the bets are off.

The bit of David's post that I disagree with most strongly (thanks for making me think about it again) is that he's mixing up energy ("lazy..." ... "should move herself") with force. What I've been trying to say (not withstanding the differences in the way that it seems David and I lead, according to FoxyLady) is that is possible, and desirable sometimes, for the man to provide strong force in his leading hand for the lady to push against yet for the lady (by pushing back against that force) still to move herself. He being strong isn't (always) an invitation for her to be lazy. He can be strong so she can be energetic.

If DavidB is saying that in no cases does the lady ever push against the man during the course of any (non-aerial, regular, lead-and-follow) move, then, respectfully, I disagree.

DavidB
31st-May-2006, 03:05 PM
The bit of David's post that I disagree with most strongly (thanks for making me think about it again) is that he's mixing up energy ("lazy..." ... "should move herself") with force. What I've been trying to say (not withstanding the differences in the way that it seems David and I lead, according to FoxyLady) is that is possible, and desirable sometimes, for the man to provide strong force in his leading hand for the lady to push against yet for the lady (by pushing back against that force) still to move herself. He being strong isn't (always) an invitation for her to be lazy. He can be strong so she can be energetic.

If DavidB is saying that in no cases does the lady ever push against the man during the course of any (non-aerial, regular, lead-and-follow) move, then, respectfully, I disagree.
And now you are confusing leading & following with connection. They are not the same thing.

El Salsero Gringo
31st-May-2006, 03:14 PM
And now you are confusing leading & following with connection. They are not the same thing.I don't see that helps us out any. If you say that
For normal vertical dancing (ie no drops, leans or aerials) then the force comes from the lady's legs, not the mans arms.then you're saying - well - no force comes from the man's arms. That's the bit I disagree with most.

DavidB
31st-May-2006, 04:01 PM
I don't see that helps us out any.
If you say thatthen you're saying - well - no force comes from the man's arms. That's the bit I disagree with most.
No force (other than enough to move the lady's hand) should be used for leading.
A force can be applied in response to the lady's following. That is not leading, that is maintaining the connection.

This is not just me being lazy. Applying force while leading is dangerous to the lady. It is unlikely to result in a dislocated joint, but it is very likely to lead to repetitive strain injuries after a few years, or aggravate an existing injury. Just watch any couple on the floor, and see the amount of movement of the lady's shoulder, elbow and wrist. It is unlike anything they do outside of dancing.

However if the lady is in a position to apply some force herself, then presumably her joints/muscles/tendons etc are lined up in a way that is not uncomfortable. I can then match the force she is applying. The problem is that she can injure me doing this. She needs to know when to do it, and I need to know when to be prepared. I don't do this with anyone except Lily.

El Salsero Gringo
31st-May-2006, 04:33 PM
No force (other than enough to move the lady's hand) should be used for leading.
A force can be applied in response to the lady's following. That is not leading, that is maintaining the connection.

This is not just me being lazy. Applying force while leading is dangerous to the lady. It is unlikely to result in a dislocated joint, but it is very likely to lead to repetitive strain injuries after a few years, or aggravate an existing injury. Just watch any couple on the floor, and see the amount of movement of the lady's shoulder, elbow and wrist. It is unlike anything they do outside of dancing.

However if the lady is in a position to apply some force herself, then presumably her joints/muscles/tendons etc are lined up in a way that is not uncomfortable. I can then match the force she is applying. The problem is that she can injure me doing this. She needs to know when to do it, and I need to know when to be prepared. I don't do this with anyone except Lily.I'd be interested to have, for instance, Andreas's opinion on the forces involved in leading Salsa. Nothing I've ever lead in Ceroc is more forceful than in Salsa, or in the little ballroom rumba, cha cha, waltz, lindy or WCS that I've learnt (such as in a basic sugar-push). Yes - forces are involved, and in a dynamic dance I don't distinguish between providing them as part of connecting back to the lady, or leading her. It's a smooth continuous flow, and such forces, light as they may be, don't come as any surprise to her.

foxylady
31st-May-2006, 06:02 PM
Actually that leads to a simple question. FoxyLady - can DavidB lead you through triples and double-time moves without extra force?





Hmm, am loath to get back into the fray here, but for what its worth, DavidB wouldn't 'lead' a double/triple spin, he would put me into a 'musical' position that suggested a double or triple was appropriate, and it would be up to me to take him up on it... and I can quite easily do a double/triple by myself, but possibly not double time...

If 'led' by ESG, he is more forceful, and he would probably give me that extra momentum to do it double time if I chose to do it, but thats only because I can't currently do it on my own; if I could I wouldn't need him to....

Some men do shove.... As Lory says a shove is when more force is used than is necessary. The amount of force needed will vary from woman to woman, which is why a 'led' dance is a very different one to one that relys mostly on equal and opposite connection.... I believe that the longer one dances and the more one gets used to adjusting to the lead or the follow one find oneself with the more one dances connectively..... (or perhaps I'm just talking a load of b*ll*cks)


Foxy

LMC
31st-May-2006, 08:34 PM
The amount of force needed will vary from woman to woman, which is why a 'led' dance is a very different one to one that relys mostly on equal and opposite connection....
:yeah: - and size/weight* is not important in this instance.

*of the follower. Honestly.


I believe that the longer one dances and the more one gets used to adjusting to the lead or the follow one find oneself with the more one dances connectively..... (or perhaps I'm just talking a load of b*ll*cks)
Variety of dance partners definitely helps IMO.

But the more I think about all this, the more I realise that what Franck calls the 'internal connection' is key to getting and maintaining a good connection with your partner. Must get back to those yoga classes.

MartinHarper
1st-June-2006, 12:51 AM
Witterings of an intermediate, past midnight, etc. Caveat lector.

Dynamic stability is a phrase used to describe some modern aeroplanes. Simply, this means that they're naturally unstable and prone to flipping upside down and falling out of the sky. The thing that prevents them from doing this is clever software that continually applies very small changes in thrust and whatnot in order to keep them airborne. Without the software, they'd go barrelling headlong into the nearest mountain range.
People are also dynamically stable, which is why we can't fall asleep standing up. When we stand up, we're continually making tiny (normally subconscious) muscle movements to keep ourselves upright. I hope that comparing followers to fighter jets is marginally more flattering than comparing them to shopping trolleys and/or perfect spheres.

A follower has her weight on just one foot at a time, often the ball of one foot. This makes her less stable - she's still stable, but only just. A very small push on her back is required to disrupt her dynamic stability, and cause her to move forwards. She resolves this disruption by taking a step forwards onto her other foot. Again, this is pretty instinctive stuff, or at least learned at an early age.
The trick is the size of the step. Normal folks take quite a large step, end up with their weight distributed between both feet, and so don't go very far. A follower will take a smaller step, so her weight ends up completely over her other foot. Ideally, this leaves her with some residual forward momentum, which causes her to again lose dynamic balance, and take another forward step, and another. Thus, when a follower is lead into forward motion, she remains in motion until acted upon by another force. She is behaving similarly to an object with low mass and low friction.

The leading force is significant, at least in this model of leading a simple forwards walk. A very small force will unbalance the follower slowly, causing her movement to be delayed and slow. A slightly larger (but still small) force will unbalance her more quickly, causing faster movement. A shove would have broken the delicate balance of dynamic stability, probably causing her to spread her weight between both legs and thus become temporarilly unleadable. In this simple scenario, the upper limit of the force you can apply on a follower is determined primarilly by her ability to remain stable and balanced when pushed around. There are other limits, but they are not relevant. The force required to unbalance someone on one foot will not tire out the leader, nor will the pressure be sufficient to cause pain (assuming one doesn't lead with a pin). Because we are leading the torso directly, frame tension is not relevant, though it would be in other situations.

The majority of the energy comes from the follower for this walk - both starting the motion and remaining in motion. However, she may not recognise this as such, just as we do not recognise the energy we expend to remain standing up. This gives rise to the sensation of being whisked effortlessly around the floor. It's an illusion, but it can feel very real, to both leader and follower.

-------
Rotation + Math.

What about rotation? Well I'd really like to do accurate calculations on that from a F=ma view first, but my rotational mechanics is all rusty. Still, I'll give it a shot and let more scientifically literate folks call me out. Leader is doing work, applying a force over a distance. On a Ceroc spin, a reasonable amount might be 10N over one meter. Energy expended = 10J.
Moment of Inertia of a follower, theorised as a solid cylinder (better than spheres, anyway). I'll go with DF's estimate of a mass of 60kg, and further assume that our follower has a circumference of 0.6m, so a radius of 0.1m. That means a moment of inertia of 0.3 kgm².
We want to get our follower spinning in time to do one spin in two ceroc counts = 4 beats. For a 240bpm song (fast), that's 1 revolution per second, or about 6 rad/s. That means we need to give her rotational energy of around 5J. If we wanted her to do a double time spin, we'd need to give her rotational energy of four times that: 20J. If we were leading a woman weighing 120kg, we'd need to give her twice the energy: 10J.

The energy input versus energy output is the same order of magnitude, which is promising. I'm going to stick my neck out and say that when a follower is put into a static single spin, a decent proportion of the energy can come from the lead pushing on her and/or her pushing on the lead, without this causing serious injury. Typically a chunk of energy will come from the follower stepping onto her spinning foot, as part of the "staying upright" energy described earlier, but this is not required.

Predictions from this theorydancing:
1. Heavy folks will be able to follow movements back and forth as lightly as others (or lighter), but will feel weightier in some spins.
2. Double-time spins require around four times the force, and are thus significantly harder to lead than single-time spins.
3. Leading a follow to step onto a foot and spin on it is lighter than leading her to spin on the foot she's already on.