Interactive Forum: Hand and Forearm Motion

[johnyandell]

[johnyandell]

I think there is a reason for the closed face, which I never used to believe but have altered my opinion after talking with Brian Gordon.

I love this clip for several reasons. First you can see that with the closed face, the rotation of the arm backwards (external) is going to be increased. According to Brian this is good mojo (not his term) for the forward rotation because of what it does to the muscles before they rotate forward.

So that's one thing.

The other is the wrist release, so called. If you watch it's obvious that the amount of wrist lay back decreases at the start of the forward swing. Doesn't make it to neutral, but it's like 30 degrees or so, maybe less. Watch however, after the hit.

See the lay back increase slightly (but unmistakably)? The force of the hit forced it back a little and you can see this effect in many many other examples from the high speed footage across many players.

What this is showing is that the forward wrist flex, snap, whatever you want to call it is basically passive.

[evikshin]

John,

Do you think the amount of wrist lay back at impact varies with the shot that te pro is trying to create? There are a some videos which show Federer with a severe laid back wrist at impact, and some other videos which show him with slightly less lay back. I still haven't figured out if this is due to different in visual perspectives of different camera angles, or if the wrist angle does indeed change.

[cyberhound]

Comparable video clip

http://www.tennisplayer.net/members/high_speed_archive/pro_men/roger_federer/v2/roger_federer_high_speed_v2.html?FHInsideOutFront-0011027-0001.mov

The above clip is somewhat comparable. However the angle blocks the block's the portion where the racquet lays back so the effect of what you see is diminished.

You can still see that the racquet lays back as an inertial lag after the legs start to drive and the hips to rotate. To get this effect the arm and wrist have to be relaxed. The body swings the arm and cracks it like a whip much the same as on the serve. Other than maybe some course correction you don't swing the arm at all. Its like rubber pole with a weight on the end that is being swung from the body.

The other thing to observe is that the movement of the white wrist band slows near the contact point. The racquet on the other hand accelerates around it in a plane tilted forward and upward at 30-40 degrees (can't tell the exact angle just a guess). After contact the wristband begins to move faster again.

The video I can't upload shows this to a much greater degree because the angle it is taken (also the front) shows the racquet lay back as well. You can then see the layback angle decrease as the forward swing unfolds and the wrist/wristband slow drastically close to contact and the racquet whip around it.

I agree the only way to get this action is to be relaxed and let the body whip the arm via the stretch shortening reflex. (passive) as opposed to trying to do it conciously.

[sticks]

I see external (or backward) forearm rotation. For me, that is what "drops" the racquet head back, inside of, and below the hand and ball. Also, it adds to the various spring effects.

[johnyandell]

Well, I wouldn't say it was all body and no hand--you have to extend the hand and arm to get through and to get to the extension and followthrough positions, especially with a 13oz implement in your hand. There is use of the shoulders and the biceps and probably some other muscles as well.

Otherwise you'd see the dissipation of the energy and the length of the motion much sooner.

Here's the clip you mentioned:

[johnyandell]

Evi,

I think what you see is the most lay back on the inside balls, especially inside out, and the least on the wide balls where the players are hitting short and crosscourt. Balls in the middle of the court are usually somewhere in between.

The tip of the racket head is traveling in the direction of the shot longer going inside out, and is coming around sooner on the crosscourt. With the arm somewhat relaxed, this is going to effect the angle of the wrist.

If in the aforementioned Tennisone clip--which I've have looked at--the ball is inside, but low and the player is trying to hit heavy topspin, the same point applies--again the shape of the swing path dictates.

By the way, the second shot in that sequence is a swinging volley--not a groundstroke.

The most important point I think is that this effect, to the extent it happens, just happens.

[EricMatuszewski]

One more part to consider...

I'm intrigued by John's and cyberhounds observations regarding "slowing down" or backward movements of the hand close to contact. So I'd like to include another thing to think about.

Energy cannot be destroyed it can only change form. (Newton)

At impact (an elastic collision) the ball compressess (storing energy) and the strings stretch (storing energy). The stored potential energy gets "released" and becomes kinetic energy once again as the racket and ball get propelled away from each other...

As a result of this event the forearm musculature (especially the flexors) are likely put on another sudden stretch which would cause another
stretch reflex. This "second" stretch reflex action would explain the slight degree of flexion that the hand eventually
acheives in the latter parts of the follow thru long after the ball has left. It would also explain the "slowing down"
of the hand at contact or any "backward" movements of the hand before it starts flexing again.


Also, just a reminder, you guys have spent very little time disscussing the whole pronation event, the overwhelming majority of the discussion seems to center more around the flexion portion which has been around since wooden rackets.

The pronation movement is much more a characteristic of where graphite tennis is and where tennis seems to be going. So lets talk more about it.

[EricMatuszewski]

I also downloaded the T1 clip you guys discussed. It's nice to see the way the ball changes spin from incomming (I think the opponent just sliced) changes to Feds heavy topspin.

Front view @ 250fps from more of a distance gives a nice view of this.

I think the tennisplayer compression of the high speed stuff is a little better though. The T1 stuff looks grainey.

[cyberhound]

pronation

.........
Also, just a reminder, you guys have spent very little time disscussing the whole pronation event, the overwhelming majority of the discussion seems to center more around the flexion portion which has been around since wooden rackets.

The pronation movement is much more a characteristic of where graphite tennis is and where tennis seems to be going. So lets talk more about it.

I think that most of this movement is pronation and there is some radial deviation of the wrist. When the stretch cycle is inititiated by the hip and shoulder turn, the racquet is facing downward with wrist relaxed with head point away to the right between 45 to 70 degrees backward. Head as much in line with the ball as possible. The effect is more exaggerated the more to the side the racquet faces. Movement and inertia with the face down cause the action to be a twist (supination of the arm) and ulnar deviation of the wrist.

Coming forward this unwinds right before contact as pronation of the arm and radial deviation of the wrist. (At least I think of it as ulnar to radial snap, It may just be quick pronation.) This whips the racquet around and the follow through is the wrist break and arm rollover that you see in the finish. But this action initiates the motion and causes the follow through.

I don't pretend to be Federer or even to try to copy him, but I hit my forehand using the stretch shortening technique with a 13.5 oz. Pro Staff tour 90, The old version not the ncode, grip in the Federer to Agassi range. If I want more topspin, I try to increase the ulnar to radial snap of the wrist which initiates the arm pronation. This will give more topspin with the same swing plane. Otherwise for a lot of topspin, I drop the racquet arm a below the ball more to increase the angle of the swing plane and still do the ulnar to radial snap. If I'm not thinking about topspin, the parts of the swing that I notice are the prep (racquet hand at shoulder level racquet pointed the right and slightly upward. Letting the racquet fall (by gravity not pushing down), opening the left hip, arm stretching and unstretching and that's it. Nothing else untill unwinding for recovery.

The follow through is lower by the hip when the racquet head starts lower and the arm finishes more and between the elbow and shoulder for a more level swing through the ball.

[gzhpcu]

I see it the way you describe it cyberhound. IMHO, ulnar to radial snap of the wrist has to be done consciously. It does not just happen.

[sticks]

I beg to differ if still photo 2 of Federer is prior to contact. It clearly shows that the wrist has flexed greatly from photo 1. In photo 1 it is layed back. In photo 2 it has flexed almost to neutral.

Besides the if you look from above the flex is not moving the racquet right to left which would destroy all control. It is moving it up and down. The plane of the racquet stays perpendicular to the flight path and the combination of arm pronation,flex and radial deviation moves the racquet head upward. This adds a lot of spin while allowing the swing plane to be through the ball.

Edit: It appears that photo 2 is about a 1/10 of a frame after contact. There is no way the wrist could fully release in the small amount of time between contact and the photo. I believe that if we had a higer speed sequence we could see that it was released or releasing at contact.

I agree that wrist flex is in play somewhat and the forearm is rotating at and through the contact phase. For me, the laid back wrist idea is more like a lacrosse action. I catch the ball and fling it back. I have to feel that I make contact and keep the racquet on the ball as it changes direction and spin. When I watch the pros, their misses appear to me (especially the women) to come from a "hit" or "slap" action. Another good image is just a serve in another plane.

[sticks]

RE: wrist snap

This is a beautiful super slo mo of federer's forehands, shot from the side view.

http://youtube.com/watch?v=xNPaZj4yn00

Pay particular attention to the second forehand he hits, as this is a side view, and thus, less deceptive.

Also, check out this

http://www.tennisplayer.net/members/high_speed_archive/pro_men/roger_federer/v2/roger_federer_high_speed_v2.html?FHCenterSide-0002720-0001.mov

The wrist appears to be laid back at least until the ball has left the racket. Watch it frame by frame. I don't see any flexing of the wrist foreward in the impact zone.

From this view, one can say that his wrist is definitely not neutral, or even close to neutral (if by "neutral" you mean the hand is in a straight line with the arm). The wrist definitely does not appear to be released, or releasing through impact. On the contrary, it almost appears that has the ball collides with the racket, his wrist gets slightly more laid back for a very short duration. His wrist appears to release when his hand is about level with his left shoulder.

However, someone else pointed out that Federer hits many different forehands--Meaning the degree to which his wrist is laid back at impact may vary, but I've never seen Fed with a neutral wrist, IF by neutral wrist you mean the hand being straight in line with the wrist. There is always some degree of lay-back. I think you'd agree with me on that.

In fact when I re-watched the first video (posted above), the first forehand in the sequence appears to have a less laid back wrist at impact, but again, the angle may make it deceptive, so I don't know for sure. I think viewing the forehand from the front is deceptive. to really see the relationship of the hand to the forearm, you need a super slo mo shot seen from the side.

Best wishes,
Evikshin

If I lock my wrist, and there are devices to help you do this for both golf and tennis, I get nothing on the ball compared to a free wrist -- both pace and spin. The question is what can the player sense and when?

[sticks]

I would agree that there is always some degree of layback. When I say neutral, I mean an unstressed position that is close to a handshake position which has some degree of layback. Also, I don't mean wrist flexion which to me means that if the the hand is pointed away from you as if to shake hands, bending the wrist so the palm faces you. I think the wrist position is used to control the direction of the ball. Severely laid back if you are in the center of the court or the backhand corner hitting to the backhand. Almost in line with the arm if you are wide to the forehand corner hitting crosscourt.

Even so It seems in the videos, that just after the motion that causes the racquet snap back that the wrist does flex forward somewhat before impact. It does seem that the angle between the wrist and the arm reduces to some degree from maximum deflection. Maybe its a visual trick.

The wrist and arm movement that I'm refering to is the change from ulnar deviation to radial deviation coupled with forearm pronation that moves the racquet from low to high through the contact zone in a plane perpendicular to the contact. The follow through of that motion is the arm lifting and turning over and the wrist flexing after contact. but to get the follow through you have to start it earlier.

The whole action is similar to throwing a frisbee with the forehand upward at a 30 degree angle.

The drill that is used to teach this is as follows:
Stand inside the service box facing the net. Hold racquet with forehand grip. Hold racquet in front of you with face parallel to ground. Hitting strings facing the ground. Have partner feed a ball to your forehand hitting position. Wait till the absolute last second. Quickly supinate the arm and ulnar deviate the wrist followed by pronating the arm and radially deviating the wrist to hit the ball over the net. With a little practice you can control the ball very well and put it were you want. Not my drill by the way, it comes from a coach on the pro tour so I probably shouldn't give it away. Incorporate this into your swing and you've got a federer-rafa-roddick-safin-like forehand.

A lot of this is difficult to see. Has anyone ever seen a racquet impart topspin (roll the ball). The ball is on the strings for so short a time the racquet imparts an unbalanced torque on the ball and the spin starts after it leaves the strings. (my opinion).

Regards,

I agree in part. I sense that the main function of the strings is to absorb the incoming forces of the ball and to change the incoming spin. In other words, to get control of the incoming ball first.

[sticks]

I'm intrigued by John's and cyberhounds observations regarding "slowing down" or backward movements of the hand close to contact. So I'd like to include another thing to think about.

Energy cannot be destroyed it can only change form. (Newton)

At impact (an elastic collision) the ball compressess (storing energy) and the strings stretch (storing energy). The stored potential energy gets "released" and becomes kinetic energy once again as the racket and ball get propelled away from each other...

As a result of this event the forearm musculature (especially the flexors) are likely put on another sudden stretch which would cause another
stretch reflex. This "second" stretch reflex action would explain the slight degree of flexion that the hand eventually
acheives in the latter parts of the follow thru long after the ball has left. It would also explain the "slowing down"
of the hand at contact or any "backward" movements of the hand before it starts flexing again.


Also, just a reminder, you guys have spent very little time disscussing the whole pronation event, the overwhelming majority of the discussion seems to center more around the flexion portion which has been around since wooden rackets.

The pronation movement is much more a characteristic of where graphite tennis is and where tennis seems to be going. So lets talk more about it.

The problem is that some have posted here and MANY have posted before, slo-mo film. That film seems to show a bent elbow, a laid back wrist and flat raquet face at impact (ie facing the net and parallel to the baseline), and a racquet that appears to have traveled through contact (long enough for ball to leave strings) evenly across the court and not sufficiently low to high to impart top spin. The pronation, wrist flexion, elbow fold, pectoral pull, shoulder rotation continuation all appear to happen long after the ball has left the strings.

Maybe these guys are all "locked-up" and have more ab/hip/leg strength than we think, and all the stuff that happens after contact is just for balance and recovery for the next shot.

Also, if we had super, super slo mo, we may see just enough pronation, wrist flexion, and low to high path to cause what is clearly evident: a forehand traveling 50+ mph (sometimes close to 90 mph !!!!), high net clearance, lands usually closer to service line than baseline (another teaching myth for club players) and a ball that bites and explodes when it lands.