Tennis Analysis with the APAS system

[uspta146749877]

Please click

http://www.youtube.com/watch?v=vgxRVfHiMio&feature=channel

[uspta990770809]

Jim must be busy

Please click
http://www.youtube.com/watch?v=vgxRV...eature=channel

I could swear I've seen Jim Shaughnessy on P90X commercials. Looks like he's into the high end video analysis. Got to be very exciting stuff, but expensive to get involved with. Is this the system Brian Gordon uses? Someone corresponded with me on something like this and it was like $100,000 for the system. Maybe a little less, but not much. You'd have to charge a lot to recoup that investment. But there are not many places that can do it.

You'll still have the problem of deciding whether you have to hit with a double bent or an extended arm!! Etc., etc.
don

[tcuk]

Wow! Whatever next. Agree with Don, though. If not cost effective, it no good to us guys.

[uspta146749877]

One more video-Ana Ivanovic Forehand on the APAS 3

http://www.youtube.com/watch?v=8VFmRECZYwQ&feature=related

[airforce1]

Is this the system Brian Gordon uses? Someone corresponded with me on something like this and it was like $100,000 for the system.

No, I'm pretty sure the one BG uses is not currently wireless.

[BrianGordon]

There are several technologies available to capture 3D motion:

Video systems require at least two synchronized cameras. These systems generally require EXTENSIVE!!! post processing (manual digitizing of the body with a mouse driven cursor). APAS is one of these - the more commonly used is SIMI - an example of which John will put forth at some point with reference to a pro serve. The more advanced of these systems can track some points (markers) automatically through surface recognition - exactly the way "hawk-eye" works. Auto tracking works very poorly, however, for complex motions like tennis strokes. The manual systems generally run 10 - 30 K.

The more advanced systems are real time (3D data produced on the spot) and are typically much faster and more accurate. The downside is that players must wear small sensors - some require power (wires as AF points out) and include magnetic field sensors and LED emitters - some don't require power instead using reflective spheres tracked by infrared cameras. These systems generally run 100 - 300 K.

I have and do use all types of these systems, and yet while very complicated, the 3D measurement is not the real challenge. More critical is how the data is processed (otherwise it is garbage) and to Don's point, what information is extracted from the measurement and how it is presented to coaches (and players) for their use - the latter being the key to usefulness to a wide swath of the tennis playing population.

[airforce1]

Brian,

Can you speak to the way the ball never seemed to actually get to the racket in this APAS analysis?

Is this indicative that much of the fine elements of the movement may be lost in translation from one medium to another?

[BrianGordon]

Brian,

Can you speak to the way the ball never seemed to actually get to the racket in this APAS analysis?

Is this indicative that much of the fine elements of the movement may be lost in translation from one medium to another?

AF-

Good observation - that jumped out at me also. Two possible explanations I can think of: less likely is a problem with the reconstruction of 3D coordinates from the multiple 2D camera views; more likely is that the ball was later graphically added for effect (not digitized as part of the data set) - think I would have made it look a bit more realistic so as not to prompt our questions!

[uspta990770809]

Advantage of motion capture

It seems to me that this technology should be great to identify whether or not the things we think are happening, actually are. And therefore, really great for research.

But I'm wondering, as a practicing teaching pro, where is the big advantage compared to what I can get with using a $400 slomo camera, my laptop, and a $40 piece of software to do side by side video analysis(V1GolfAcademy.com) to help me in my analysis of what I can't see with the naked eye.

I would expect if I had exhausted solving problems with simpler approaches and couldn't figure out why "nothing was happening" or there was insufficient power or even accuracy and consistency in a shot, then motion capture might reveal the problem. So if you do elect to see someone like Jim Shaunhessy or better, Brian Gordon, for a consultation, what is the ballpark cost for two or three sessions over time to identify a problem and formulate a process to correct it.

I'm assuming Brian can afford this stuff because he's part of a university biomechanics department. It would be nice to be near something like that and be able to access that capability when it is called for, but I don't see how I could afford to make it pay for my teaching court.

I'd love to find out that I am wrong on that!
don

[BrianGordon]

It seems to me that this technology should be great to identify whether or not the things we think are happening, actually are. And therefore, really great for research.

But I'm wondering, as a practicing teaching pro, where is the big advantage compared to what I can get with using a $400 slomo camera, my laptop, and a $40 piece of software to do side by side video analysis(V1GolfAcademy.com) to help me in my analysis of what I can't see with the naked eye.

I would expect if I had exhausted solving problems with simpler approaches and couldn't figure out why "nothing was happening" or there was insufficient power or even accuracy and consistency in a shot, then motion capture might reveal the problem. So if you do elect to see someone like Jim Shaunhessy or better, Brian Gordon, for a consultation, what is the ballpark cost for two or three sessions over time to identify a problem and formulate a process to correct it.

I'm assuming Brian can afford this stuff because he's part of a university biomechanics department. It would be nice to be near something like that and be able to access that capability when it is called for, but I don't see how I could afford to make it pay for my teaching court.

I'd love to find out that I am wrong on that!
don

Don-

As to the advantages for coaches:

First is simply level of detail. By way of extreme example, going to a coach to help my forehand using video software is analogous to me going to my very skilled physician for an office visit to assess the pain in my leg. But, unless the pain is caused by a bone protruding from the skin, my physician will send me for an MRI – 3D is the MRI of stroke analysis. The information takes much of the guesswork out of stroke assessment and provides the most rapid path for systematic intervention by exposing the causes rather than symptoms of problems. In my experience, level of detail is important for some and not for others – I prefer to have as much information as possible in my coaching and for my physician.

Second is simply perspective. The system fosters any coach’s ability, and provides the tools and information, to plan stroke development and associated training based on an understanding of the human musculoskeletal mechanics. This allows coaches to closely match stroke mechanics goals to each individual’s ability and perceived genetic capabilities. The result is the most direct path to individually optimized stroke mechanics, in the shortest amount of time, and with the smallest chance of injury.

Anyway, those are my talking points – I could go on for pages about specific benefits and when we meet at Indian Wells I promise you will be amazed by the practical as well as research implications - I'm the first to admit, however, this approach is not for everyone.

As to the cost:

I charge players a couple hundred dollars for full measurement and data presentation of three strokes (serve, forehand, and backhand). I own the systems - my applied activities (player development) are separate from my basic research in the university setting.

The technology is obviously too expensive and complicated for most individuals or tennis training facilities to operate – therefore, under the right conditions, I buy, place, and operate the capture systems at certain facilities – I hope to put a couple of LED systems in California in the next year or so – hope we can work together towards player development.

[airforce1]

"As to the cost:
I charge players a couple hundred dollars for full measurement and data presentation of three strokes (serve, forehand, and backhand)."


Sounds like quite a value to me.

[uspta990770809]

Fair price

Don-

As to the advantages for coaches:

First is simply level of detail. By way of extreme example, going to a coach to help my forehand using video software is analogous to me going to my very skilled physician for an office visit to assess the pain in my leg. But, unless the pain is caused by a bone protruding from the skin, my physician will send me for an MRI – 3D is the MRI of stroke analysis. The information takes much of the guesswork out of stroke assessment and provides the most rapid path for systematic intervention by exposing the causes rather than symptoms of problems. In my experience, level of detail is important for some and not for others – I prefer to have as much information as possible in my coaching and for my physician.

Second is simply perspective. The system fosters any coach’s ability, and provides the tools and information, to plan stroke development and associated training based on an understanding of the human musculoskeletal mechanics. This allows coaches to closely match stroke mechanics goals to each individual’s ability and perceived genetic capabilities. The result is the most direct path to individually optimized stroke mechanics, in the shortest amount of time, and with the smallest chance of injury.

Anyway, those are my talking points – I could go on for pages about specific benefits and when we meet at Indian Wells I promise you will be amazed by the practical as well as research implications - I'm the first to admit, however, this approach is not for everyone.

As to the cost:

I charge players a couple hundred dollars for full measurement and data presentation of three strokes (serve, forehand, and backhand). I own the systems - my applied activities (player development) are separate from my basic research in the university setting.

The technology is obviously too expensive and complicated for most individuals or tennis training facilities to operate – therefore, under the right conditions, I buy, place, and operate the capture systems at certain facilities – I hope to put a couple of LED systems in California in the next year or so – hope we can work together towards player development.

If someone is spending almost $4000/yr for a weekly lesson with me ($80/hr), a few hundred for a once or twice a year analysis to see how we are doing and recommend a possible correction and protocol would make a lot of sense. I know I have a couple of students who would consider something like that. However, some of the same people have trouble responding to the most basic of requests. Will they respond better to motion capture? Perhaps.

don

[mntlblok]

"As to the cost:
I charge players a couple hundred dollars for full measurement and data presentation of three strokes (serve, forehand, and backhand)."


Sounds like quite a value to me.

I sure saw it that way. Plus, just getting to talk to someone like Brian and pick his brain was really cool for an anal retentive like me (I). He definitely knows his stuff. Looking forward to more of his articles.

Kevin
Savannah