The Forehand: Busting misconceptions once and for all

[Chas Tennis]

Originally Posted by Kevo

.............................................
Also, hitting the ball with your weight(mass) moving forward rather than swinging makes for some of the most spectacularly power volleys I have ever hit. It's amazing really how much hurt you can put on the ball with a step forward and a slight forward movement of the racquet. It's really a shame I don't typically move properly up to net and I like to swing too much.

I agree.
An instruction video, Volley Secrets, that supports the view of step forward as you volley.
http://www.youtube.com/watch?v=fJb954_II7c

Why do you think moving forward relatively slowly at maybe 10-15(?) feet per second, slow compared to the ball velocity, adds so much stick to your volley?

[Chas Tennis]

Originally Posted by Chas Tennis

On looking at videos of serves I believe that most servers hit in the top half of the racket face. I have not done stats which are often surprising. I would like to have a more scientific basis for a conclusion and there probably are research papers but I don't know about them.

I have looked at fewer forehands and have done no stats again but I believe that most strong forehand ATP pros (I have not looked at as many WTA forehand videos) hit topspin drives in the bottom half of the racket face. Nothing know as to whether they 'deliberately' hit in the bottom half but I believe that that do. They may not know where they hit very accurately unless they use high speed video.

How would you bet on the question? - Do most pros hit forehand drives by contacting the ball in the top half of the racket or in the bottom half? Would you need odds to bet?

Interested parties can find high speed videos of top 20 players that show top spin forehands where the position of the ball contacting the face can be clearly seen. These are hard to find as the shutter speed has to be fast to reduce motion blur and the frame rate had to be high >200 fps to increase the chance of catching the ball in contact with the strings. The ball has to be seen in contact with the strings otherwise it can be deceptive due to the viewing angle. No cherry picking, randomly accept whatever videos clearly show the impact location... You might also note how the racket face turns just after impact. Identify the video and give the seconds shown on the screen. Post results - top half - estimate from center or bottom half estimate from center. How to divide the racket face into fractional areas since inches are more difficult to calibrate........?

Youtube or Vimeo do not have good stop action. If you click the play-pause button with your mouse as fast as possible you often can get ball contact.
CORRECTION: I just used YT on this video and could use the forward and backward arrows to stop action single frame. This is a big improvement.

Tennisplayer.net has stop action as well as some other sites. In Quicktime the forward and backward arrows are used for single frame.

About 50 observations total should show how often the pros are hitting forehand drives in the top or bottom half of their racket faces. If a few good citizens could do 10-15 each we could get a preliminary answer.

CORRECTION: On this video I could use the forward and backward arrows to do stop action single frame on Youtube. A huge improvement for analyzing high speed videos of tennis strokes.

See second 27 for Almagro contacting the tennis ball.
http://www.youtube.com/watch?v=ekb4AqquFL8

[Kevo]

Originally Posted by Chas Tennis

Why do you think moving forward relatively slowly at maybe 10-15(?) feet per second, slow compared to the ball velocity, adds so much stick to your volley?

I believe it's a combination of things, but the basic answer is when the form is correct the ball sees not just the mass of the racquet and arm, but much of the bodies mass as well.

Think of it like getting hit by a cyclist at relatively high speed versus getting hit by a truck at low speed. The energy from a massive object even at slow speed is much higher.

[luvforty]

Originally Posted by Chas Tennis

I agree.
An instruction video, Volley Secrets, that supports the view of step forward as you volley.
http://www.youtube.com/watch?v=fJb954_II7c

Why do you think moving forward relatively slowly at maybe 10-15(?) feet per second, slow compared to the ball velocity, adds so much stick to your volley?

body moving 10 ft/sec.... but the arm is also moving forward, so the combined speed is bigger.

body moving forward is more of a necessity to find the ball.... i can hit a volley almost equally hard without body moving forward if the ball is within reach.

you do swing to hit a penetrating volley.... but beginners swing the wrong thing.. they move the racket head, but the elbow is almost static, so there is no mass behind the collision.

Oscar has a video about 'leading with the hand'... it works for his teaching... but i would teach 'moving the elbow at the same speed as the racket head'..... this way you keep the face angle the same, and you have mass in the collision.

with a firm grip, let's say the collision is almost elastic.

then

m1v1 + m2v2 = m1v1' + m2v2'

and

1/2 m1 v1 (sq) + 1/2 m2 v2 (sq) = 1/2 m1 v1' (sq) + 1/2 m2 v2' (sq)

in other words, conservation of momentum and kinetic energy.

and you can plug in a few numbers, and realize that to achieve the maximum v2' (ball speed), the key is to increase m1 !

so you make the collision unit bigger, not just the racket head, but the entire arm/racket unit.

[Chas Tennis]

MYTH: Strings that don't need re-straightening, don't move.

REALITY: Some popular modern strings such as Luxilon don't require re-straightening because they slide more easily according to the video in this 2011 story. Similar to Wilson commercial, Jan 2013.

See video.
http://www.theatlantic.com/magazine/...tennis/308339/

[Chas Tennis]

Stop Action with DVR. I looked at the clear high speed videos presented on the 2013 Australian Open by ESPN & Tennis Channel. I used my DVR to do stop action. Both ATP & WTA players. Only used videos that were clear with small motion blur. (Rejected double image effects probably due to unknown interlacing effects). Record keeping was poor, about 10-12 total.

These videos were usually winner highlights, where the players appeared to be in good position and intended to hit a very strong forehand. I don't believe that any were of shots that went out.

If the bottom/lowest frame edge of the racket were 0, the top/highest frame edge were 10 and the center line (handle center line extended) were 5 then

the ball hits were in the 4-6 range. I did not see any impacts that were way off the centerline.

Estimating impact spot, where 5 is the center line and the racket face is divided 0-10 bottom to top:
Li Na - 5, 6
Sharpova - 4, 5
Tipsaravic - 4
Some others also.....

I had intended to analyze more high speed videos shots just as Toly has done but have not gotten to it.

I had originally thought that pros deliberately or by trial-and-error practice were hitting most balls in the lower half of the racket face (say at 3 as defined above). Now I don't believe that. I intend to farther analyze videos for this issue as I come across them. The issue could be farther researched.

High Speed Video Analysis Issue- Racket is Rising Rapidly at Impact. One point is that for the current forehand with its rapid rise of the racket at impact, when you look at a high speed video and see ball impact, on the very next frame at 200-300 fps the racket will will have moved considerably higher. Not doing single frame analysis may produce a false conclusion as to where the ball was on the racket face at impact. Requires targeted high speed video with a clear view of the racket face, high frame rates >200 fps ?, a fast shutter speed for small motion blur, and observing ball impact on the strings. Any rolling of the ball on the strings makes analysis less accurate. Both the rapid racket motion up and the ball rolling on the strings might make the ball appear to initially hit low on the racket face if not carefully measured. I think that's what fooled me.

An interesting related question - Do I hit long and in the net because I am hitting high or low on the racket face - much more than the pros do - and the racket tilts while in contact?

[HSCoach]

Originally Posted by 10isfreak

yet an other possibility is that of a combination of sliding ball and moving ball.

I expect we know the above is the case. For this discussion, if a ball contacts the strings in the exact center, then slides a couple of mm down during the dwell time, would you call that a center hit or below center hit? thanks.

[Chas Tennis]

Originally Posted by HSCoach

I expect we know the above is the case. For this discussion, if a ball contacts the strings in the exact center, then slides a couple of mm down during the dwell time, would you call that a center hit or below center hit? thanks.

I'm not sure who you are asking. I proposed a question only about the initial ball contact location, first contact, and a simple way to crudely observe it with videos.

Originally Posted by Chas Tennis

.............................................
About 50 observations total should show how often the pros are hitting forehand drives in the top or bottom half of their racket faces. If a few good citizens could do 10-15 each we could get a preliminary answer.

If we had observed lower impact points then it would be interesting and need better measurements with higher speed cameras to see the entire ball contact time. Videos of this quality are probably not available for pros on the internet, Nadal's entire contact time at 5000 fps, etc.

I would call your example a center hit, a 5. The accuracy of these crude measurements is not expected to be "a couple of mm", it's probably not even +/- 2 cm. I divided the racket face width into 10 parts and estimated by eye which part it mostly hit in. My racket face is 27 cm across and 1/10th of that would be 2.7 cm. Saying it hit at 6 means that it is estimated to be closer to 6 than to 5 or 7.

This is just a crude measurement intended for a quick look to see if the balls were systematically hitting low, say, around 3 which was my best guess before looking more carefully at some videos.

This little myth may have cost me because I actually thought hitting in the bottom half might work better than hitting in the top half or centerline. It still might for my stroke if the racket tilt after impact has some affect. Next, I will be looking for how far off the center the hits are and how the racket tilts.

[HSCoach]

Originally Posted by Chas Tennis

I'm not sure who you are asking. I proposed a question only about the initial ball contact location, first contact, and a simple way to crudely observe it with videos.

thanks for your answer and I agree this is a challenge with most available video. With high speed video on strong top spin shots, there are 2 points of reference (at least) for us. One is the initial contact you suggest and the other is location at full pocket depth. seems the full pocket depth is lower and more indicative of the action you expect.

[Relinquis]

Surely the greater forehand misconception is that players are able to hit the ball 1-2 cm below the centre of the racquet consistently...

[sureshs]

http://tt.tennis-warehouse.com/showthread.php?t=453098

[HSCoach]

Spadea busts misconceptions

Originally Posted by sureshs

http://tt.tennis-warehouse.com/showthread.php?t=453098

actually seems he may just be reinforcing a few of the old ones?