James's Forehands - Part II - 16/06/11

One week later James and I went back on court to improve his forehands. The main thing was to raise the right elbow with the unit turn. I think it looks much better...



After the turn, James has his shoulders perpendicular to the net. He can turn another 30, or 40 degrees more. To do that he needs to stretch his left arm more on the power position and he needs to open his stance more and getting his left knee lower. Notice how on his last step, James steps forward with his left foot. Instead he could have stepped towards his left increasing his open stance and getting lower, ready for the forward swing. Of course to do that he would need to move in closer to the ball.


This second video is an interesting footage. This is the video James needs to watch to know where to go next. This was the only forehand that I've recorded that James had a shoulder turn of about 110 or 120 degrees to the net and his hips were perpendicular to the net on the power position. Although James didn't really attacked the ball and his swing seems to be a bit too big because the position of his right hand is too far to his left side, its still a great shot and the one that going to change every forehand that James will hit in the future.

On this forehand James has elevated much more his right elbow, roughly shoulder high. He kept the left hand on the racquet longer and he had a much bigger turn. His shoulders went much more than perpendicular. Just before the power position (moment before the forward swing) his left arm is back because he kept it longer on the racquet while turning his shoulders. If James can have roughly the same sort of turn with the left arm straight for the power position would be even better. And again the left foot is too close to the right foot while striking the ball and as a consequence he is too upright and unbalanced.


The third forehand resembles a bit the first one. The elbow was a bit lower. The left hand got away from the racquet earlier and the turn wasn't as big as on the second shot. One improvement from the first forehand was that on this shot James used his left foot, on his last step, to increase his stance. Although the left foot went too far back which makes it very difficult for James to have his hips perpendicular to the net.
This is another point where James can be aware on his forehands. Compare the hips position on his forward swing on all of the videos. On the second video the hips were perpendicular to the net, but videos 1 and 3 weren't.



On this last video, James started with a higher elbow, but not as high as the second video. James again couldn't have the same turn as on that 2nd shot and his hips didn't get perpendicular to the net.




After having a good look at James's forehands we know already with more certain what James needs to do next.
James future forehands will have the same shoulder turn of video 2 , his hips will be perpendicular or more at the start of the forward swing, his left arm will be stretched out and he will have a wider stance. Besides, he will be hitting his forehands with his right hand more on the right side of the body.

This next picture is from shot 2. Watch the shoulder turn and hips perpendicular. If James can have the same turn while having the left arm out and straight his forehands will get extremely hot! Watchout!















This is me on the power position. Check the shoulder line, hips, left arm, left knee.

James's Forehands 09/06/11

Tony's forehands side view

25/05/11

The myth of the Ball trajectory on the serve - part2

I've been quite curious and interested about the trajectory of the ball after impact on a serve. You can see my previous article about the myth of the upward trajectory of the ball after contact on the tennis serve :

http://andrevazpinto.blogspot.com/2011/03/myth-of-upward-trajectory-of-ball-on.html

In fact what I've been discovering on the tennis court with more and more videos is that the trajectory of the ball doesn't depend mainly on the height of the contact point, but is more dependable on the speed and spin of the ball. That is true of course until a certain extent, there are many different variables all working at the same time, like height of contact, position of the racquet, spin, speed, etc.

If you watch the last video of Adam at 200 frames per second, serving from the side view, you can see that the ball right after contact is getting lower and lower. At least, we can say without a doubt that there is a tendency for the ball to drop after contact. Of course some can argue that we can't really see the ball clearly and that we need to increase the amount of frames per second on the video footage so we can be sure.

It is interesting to see the same pattern of the flight of the ball on James's serve recorded at 1000 frames per second:

http://andrevazpinto.blogspot.com/2011/03/james-serves-at-1000-fps.html

When I showed this footage to one of the coaches one question was raised: 'how can we be sure that the ball is not staying leveled or even going up for a millionth of a second after contact before it starts dropping?'

I think that the best answer to that question is that in fact, from physics we know that it is impossible for the ball right after contact to stay at a leveled height. At a microscopic level the ball is either going slightly up or down. If it was true that the ball after contact first goes goes up and then it curves down it would be extremely easy to see that on camera since the arc of the ball would have to be very clear.
We can't forget either that the ball before being hit on the serve is accelerating downward and it is not on a stationary position.
What about the topspin, wouldn't that be able to create that looping of the ball extremely fast right after contact?

That is not possible, first of all it is impossible to create perfect topspin on the serve as J.Yandell has already demonstrated. There is always a side component on the serve and that makes it even harder to believe that the trajectory of the ball on the serve first goes up and then magically drops straight without we being aware of it not even at 1000 frames per second. Every shot we hit with topspin we create a long arc since we have to hit the ball over the net. For us to create a short arc we would have to be very close to the net and compromise substantially the speed of the shot.

There might be a few exceptions (although I haven't witnessed that on the pro game) but in general the trajectory of the ball after contact on the tennis serve is downward for either first and second serves.

Adam's serve

25/05/11

Adam's Forehands

Here we have Adam's Forehands recorded on the 25th of May 2011.

In general I think Adam has achieved already an efficient swing.

He starts his swing with a unit turn. As his turn his shoulders he elevates and pushes back his right elbow making the racquet head tilt down towards the ground. His right elbow is quite high even passing the height of right shoulder. F.Gonzalez is a player who elevates the right elbow higher than his right shoulder while preparing his forehand. At this moment he still has both hands on the racquet. He turns his feet to the side and his whole body gets low. He seems very well balanced and he is ready to attack the ball!



After releasing the left hand Adam starts preparing his power position. (The power position is achieved just before the forward swing when the body is ready to explode to attack the coming ball). It is here that I've found one important element for Adam to improve his forehand. Before reaching the power position Adam drops his right elbow quite considerably as his racquet gets vertical. Although the front video view is not the best to see the height of the elbow on the end of the backswing with help of my software I could see a a little bit of Adam's elbow. (If you can't see it here, you have to take my word for it). Have a look at Gonzalez's elbow at the end of his backswing:






Apart from the drop of the elbow which I think can make a huge difference on Adam's forehand, the other fundamental aspect has to be his extension which is very minimal. His right elbow after contact is going extremely close to the body.

Adam needs to finish his right hand and elbow further in front of the body, even when he his hitting flat. r.




The next picture I am hitting a flatter shot. Notice how my right hand and elbow finish more in front of the body.



The great thing about high speed video is that it gives us a great awareness of what we are doing. The more I watch Adam's forehands and compare it with the pros and even with my own forehand the more I learn about it.

Richard pointed out that Adam seems to be ready to attack the ball but then he seems to push it forward. Its like he is not accelerating through.

From the start after first watching Adam's forehand videos I had a feeling that Adam hits his shots with side spin, although I couldn't prove it even at 200 frames per second. I would need 500 frames per second to be sure. However, after looking at my picture and Agassi's at the contact point and then comparing it with Adam's shots helped to solve the puzzle. See if you can find the difference:





If you observe Agassi's (and mine) right foot position, you can see that it is parallel to the baseline. Adam has already Pivoted the right foot before contact, which means that at contact you already lost some of the power. This was true for Adam's videos 1 and 2. On video 3 Adam has his right foot similar to both Andres on contact.

There is so much more we can say about someone's shots. I think now we can say that we understand much better how Adam's strikes his forehands. The key is awareness, the rest is easier and will come with time.