Coaches Question about vault mechanics

[Geoffrey Taucer]

In vault, there are three aspects that gymnasts and coaches try to maximize; vertical amplitude (ie height), horizontal amplitude (ie distance), and angular momentum (ie rotation).

Given that the gymnast enters the vault with a finite amount of power, the power must then be split between these three goals.

If the gymnast hits the board and table at a lower angle (ie farther from vertical), more of that power will go into height and less will go into distance. The closer to vertical the gymnast is on board and table impact, the more distance the gymnast will achieve, but at the expense of height.

It seems that a lower angle (ie leaning back more) on the board would necessitate a higher table setting and result in greater height, but less distance. Hitting the board closer to vertical would necessitate a lower table setting, but increase the distance traveled.

What is the optimum balance between these two goals, and how does rotation figure in? In picturing it, it seems to me that optimizing in favor of distance over height would increase the amount of angular momentum, but I'm unclear on whether or not this would make up for the loss in height. Conversely, optimizing in favor of height might decrease the amount of angular momentum available, but increase the amount of time during which the body can rotate; Would this increase in available time make up for the loss in angular momentum?

So I have two questions:

1) First, do I have the mechanics right here?

2) What is the optimum balance to be struck between height and distance? Is it better to hit the board and table close to vertical, or is it more efficient to hit with a steeper angle? Is there a specific optimum angle on board and table contact, or does it vary depending on the gymnast and on the skill being performed?

 

[Iwannabemargo]

you also have to allow for energy conversion - ie vertical momentum converted to angular momentum by the vaulter

 

[Geoffrey Taucer]

you also have to allow for energy conversion - ie vertical momentum converted to angular momentum by the vaulter

But am I correct in assuming that angles closer to vertical would result in more momentum converted to rotation but less to height? That's what I'm getting at -- the three goals have to be balanced, and there is a certain amount of conversion between the three that can occur on board contact and on table contact. The questions are:

1) Am I correct in my analysis that contact angles closer to vertical will result in greater rotation and distance but less height

2) Is there a hard-and-fast rule for optimum balance between height, distance, and rotation.

 

[CoachTodd]

From what I can tell, 45 degrees is usually an angle for maximum height and distance when looking at things from a purely Physics point.
Having said that, it gets far more complicated when calculating what angle to hit the spring board to transition power into the springs to leave the board at the angle needed to get the correct angle on the table.
I'm afraid I haven't found the magic equation since every vaulter is different in height, speed, strength and flexibility.

Hitting at the lower angle does usually lead to better rotation but, this energy can be redirected into height as well as distance depending on the forward speed of the vaulter.

You should actually look at video of some of your own vaults. You'll notice that when you moved the board closer, you achieved more height, distance and rotation.
I think you have to look at each individual gymnast and find that sweet spot for their vault. Most of the really good ones I've seen hit the table between 30 and 50 degrees and leave the table before 65 degrees but I haven't actually measured the angles .

 

[Deleted member D3987]

bottom line...the closer the board to the table means the athlete gets on fast with no negative consequences in loss of speed to the table.

unfortunately, some kids can not cope with being "that close" in so much as they "feel" that they won't be able to turn over on to the table regardless of which vault they do. they think that they will eat their face or hit their head. not true, of course. but it's hard to battle/cope for the gymnast.

Maroney's vault was not by accident. her board is at 10 inches at the back of the board. what happens when she hits and leaves the board and table is pure technique and physics. she is also 1 of the fastest twitched kids to ever grace gymnastics. therefore, there are some kids that will NEVER be able to accomplish this task. it just is what it is.

 

[BlairBob]

Yes, the board distance for vaults for non flipping handspring vault that twist is much different than for tsuk or hand front or cuervo

Not really sure about yurchenko

 

[Gymsanity]

Not sure if you are familiar with Dr. William (Bill) Sands, but this is his bread and butter. I tend to look at things like this in more 'human' terms, but if you are looking for pure physics and biomechanics, Bill is your man. I doubt there is a single skill or event he hasn't broken down to the n'th degree. He used to use 2D and now 3D software for analysis. He used to (maybe still does) a lot for USECA and the gymnastics community as a whole. If you Google him, you might be able to find the very subject being addressed by him. Let us know.

 

[Deleted member D3987]

no longer for USECA.

 

[Deleted member 14190]

Yes, the board distance for vaults for non flipping handspring vault that twist is much different than for tsuk or hand front or cuervo

Not really sure about yurchenko

==
Yes, our regular hand springs are about 5.6 and our front handspring fronts are at 6.4, tsuks are around the same as 5.6 or 5.10 (measuring from the far side of the board).

 

[iwannacoach]

Everything's a trade-off. The kids only have so much energy produced from their run that can be sent upward and forward through the entire vault. It's a matter of choosing which directional component best favors the combination of the child's ability and the vault. Some kids lack the ability to come in at 35-40 degrees and elevate free of the table at at 70-75 degrees, but have other abilities that allow them to satlo from a block that hits the table at 60-65 degrees and elevates at 75-80 degrees. So you just have to coach to a kids strengths, if they have one to be found.

Rotation for saltos come from contacting either the board, the table, or both with a tight enough body that they tumble into rotation as a result of their base being stationary, briefly during the block, while their opposite end travels through the arch at the end of their body's length. Generally speaking it's better to decrease the block angle until they are struggling to push out of it, and then back off by a few degrees. That will usually satisfy the height and rotation requirements, and get them as much distance as they can reasonably get, unless they're one of the few who can run in at full speed and block entirely for height and rotation, and are landing just a few feet away from the table..... but that's a nice problem to have to solve.

 

[BlairBob]

Those measurements are in what?

 

[BlairBob]

Last I remember, Bill was supposed to be working at the OTC.

 

[Deleted member D3987]

no, he's now in Tennessee. he's been gone from the OTC probably 5 years now. he was at a small college in Cali the past couple of years. he just moved east recently.

 

[BlairBob]

Well there went my idea of visiting him in CoSprings. Been driving by the OTC about half a dozen times in the last year.