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Old 03-04-2011, 03:50 PM   #90
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This is the most important theoretical analysis of tennis serves you have ever seen. Its depth is huge. At first, I couldn't believe that I see a diagram so perfectly representing my way of thinking about tennis technique. After so many years, I had a scientifical proof that I was right. It was an amazing moment for me. I spent many hours talking about this image with my friend, who is coaching tennis 30 years. He was amazed, too.

Please save this image in case of hosting problems.

The image above shows kinetic energy (in joules, vertical axis) as function of time (frames, 125 Hz). It was published in 2009 in one of scientific magazines. This paper was first (ever!!!) scientific analysis of kinetic energy during serves (what, btw, shows the real level of modern tennis science...).

Two really good tennis players, 15 serves per player, 3D photogrammetry, 28 points body model, statistical analysis. You know, all that stuff...

So, what do we see? We see evolution of kinetic energy during serve from platform stance.

Ke LL - kinetic energy of lower limbs (both thighs, tibias, feet and pel).
Ke Tr - ...of trunk
Keuarm - ...of upper arm
Ke Larm - ...of lower arm
Ke H-R - ...of hand and racquet.

MER - Maximum External Rotation

I could write many words here, but I think it will be better if you try to interpret the image. I'll help you a bit.

So, guys, what do YOU see on the image above?
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