Developing an ATP Forehand:
Part 2: The Forward Swing

Brian Gordon, PhD

Page 2

In addition, in the double bend, the orientation of the upper arm is more downward (vertical to the court) near contact. Due to this contact orientation of the upper arm, the neuromuscular enhancement from the counter rotation of the shoulder (or external rotation) contributes less to vertical racquet speed.

Compared to the straight arm, this means that with the double bend the neuromuscular enhancement of the forearm from the counter-rotation in the dynamic slot plays a larger role in creating vertical racquet speed.

While there are advantages to the straight arm forehand, there are also difficulties associated with the timing of the contact point more in front. Even at the highest levels, players who use the double bend such as Novak Djokovic can have tremendously effective forehands, and the double bend is still probably the predominant arm structure, even on the ATP tour.

Laid Back Wrist

We noted earlier that the third rotation created by the flip into the dynamic slot was the laid back wrist. Unlike the shoulder and the forearm however, the wrist motion is generally not targeted for enhancement by elements of the stretch-shorten cycle.

In fact, the situation is normally quite the opposite. Instead the real role of the wrist is positional. The laid back wrist position provides the player with wrist joint range of motion needed to position the racquet head at contact.

To understand what all this means, we need to examine the forward motion of the racquet head after the transition point, when the nature of the acceleration changes.

Prior to the transition point, as we have seen, the acceleration of the racquet was relatively linear. At the transition point the racquet begins a rotational acceleration.

It has been observed by some that this rotational motion appears to be related to wrist joint motion. In fact, wrist joint motion is often evident in the high speed video, and is most obvious in the players with more the conservative grips like Roger Federer.

In Federer’s case, this forward wrist motion seems to be about 45 degrees. If you watch Federer’s forehand coming out of the slot, there is roughly a 90 degree angle between the racquet and the forearm. At contact, it has changed roughly 45 degrees.

Wrist Snap?

Many observers have concluded that this wrist joint motion is caused by conscious muscle driven wrist motion—the so-called wrist snap—and even that this motion is potentially enhanced by stretch-shorten cycle mechanisms.

Is that an accurate description? 3D quantitative data indicate the role of the wrist joint motion is actually much more complex.

Remember that the hitting hand comes out of the dynamic slot on a fairly straight line because it starts to the hitting side of the body. But as the arm passes through the torso rotation and approaches contact, the hand will start to pull in closer to the torso.

This is because the arm is rotating around the shoulder joint. The effect is that the hand starts to move back on a curve to the player’s left.

As the hand moves inward and to the left in this fashion, the force the hand is exerting on the racquet also turns inward. Understanding this is critical to understanding what is happening with the wrist.

The centripetal component (ie, towards the center of rotation) of this force of the hand on the grip would tend to cause the racquet to rotate around it own center. But because the racquet is held firmly in place the hand, this racquet rotation will only occur if joint motion allows it to do so. On the ATP style swing the wrist is the primary joint allowing this racquet rotation.

To see how a centripetal force can cause rotation of the racket, just hold onto your racquet with your thumb and two fingers and swing the arm. The racquet rotates because the force from the fingers is pulling towards the center of the rotation. Since the racquet is not being firmly held, the rotation of the racquet around its center occurs as the grip slips in the fingers.

So the motion of the hand--a combined result of trunk rotation and independent forward motion of the arm at the shoulder--creates a centripetal force. This force causes the racquet to rotate via the forward movement of the wrist joint.

This is apparent in the high speed video when we see the change of the angle of the wrist lay back between the transition point and the contact. So is this or is it not the fabled "wrist snap" that players and coaches have been debating for years?

Yes, the motion of the wrist joint is bringing the racquet head around, and yes this is contributing to racquet head speed in a significant way. But is this the result of the player’s decision to forcibly "snap" the wrist forward?

The answer appears to be no and this is one of the surprising result of our 3D research. There is no conscious forward wrist snap.

Rather than snapping the wrist forward, the muscles that control the wrist joint appear to be doing the exact opposite. These muscles are actually resisting the forward wrist joint motion.

Rather than reducing the angle of the wrist lay back, they are in fact acting in opposition to the effect of the centripetal force that is the source of the rotational acceleration. They are contracting (though eccentrically lengthening) to control the rate of racquet rotational acceleration.

Given this role of the wrist joint muscles, it seems the wrist lay back in the dynamic slot is not a counter-rotation that targets stretch-shorten cycle enhancement.

But if the role of the wrist joint muscles is not to cause racquet head speed then what is their actual function?

The answer is they have another equally vital role. This is positional. They control the orientation of the racquet at contact which is an important determinate of the shot direction.

The contraction of the wrist muscles controls the rate of the forward wrist joint motion and this is what allows the player to position the angle of the racquet head to help create the direction of the shot.

The angle of the wrist at contact controls the direction the racquet is facing. The amount of wrist motion controls the angle of the wrist.

This is why you often see more forward wrist joint motion in forehands hit crosscourt or from the right side of the court. This is also why you see less forward wrist joint motion when players hit inside out.

Timing of the Transition Point

To review, the first part of the forward swing on the Type 3 ATP style forehand utilizes a relatively linear acceleration of the racquet coming out of the dynamic slot. Then in the second part of the forward swing, there is a transition to racquet rotation at the wrist into contact.

The role of the wrist joint is therefore complex. Its movement allows the rotational acceleration but at the same time also controls the timing and the rate. This indicates an intricate relationship between the centripetal force on the racquet and the way the wrist joint is muscularly controlled.

The critical piece of the puzzle in understanding this relationship, and more importantly in analyzing the role of the wrist, is the timing of the transition point. The timing of the transition point varies from player to player. Some break the transition point sooner and others later.

Our research shows, however, that the longer the transition point is delayed, the less muscular inhibition (at the wrist joint) is required to control the rate of racquet rotation. The most advanced players for which data is available in fact delay the transition point until much nearer to contact and utilize minimal muscular inhibition.

For these players, the orientation of the racquet at contact is controlled by the timing of attaining the transition point, with minimal rotational rate control from the wrist joint musculature.

So if a later transition point is preferable, how do players create it? Quite simply, it is done by maintaining the laid back orientation of the wrist for as long as possible.

However, this is often easier said than done. The laid back wrist is created as a dynamic consequence of the racquet flip in dynamic slot. Because of this the wrist has the tendency to release forward from elastic components of the stretch-shorten cycle.

Players must consciously prevent this release from happening. And in fact, one of the major developmental problems in teaching this forehand style occurs if the wrist joint is allowed to release forward with stretch-shorten element enhancement.

In this case a noticeable "slapping" of the ball occurs. This comes with a very large contribution to the racquet rotation from wrist joint musculature. While conducive to forward speed, this decreases the vertical racquet speed enhancement that is the true goal of the dynamic slot.

There is one final finding regarding the timing of the transition point. This relates to the forehand types. In the Type 1 and in some Type 2 forehands, the transition point is reached very early in the forward swing due to the more circular swing pattern.

With these swings, the interaction between the force of the hand on the grip and the manner in which the wrist is manipulated is different than the Type 3 swing. In many cases with the Type 1 and Type forehands, the muscles of the wrist are actively used to cause rotation of the racquet approaching contact.

This finding, along with a lack of the dynamic slot to enhance vertical racquet speed, explains the effectiveness of these swings to develop forward racquet speed at the expense of vertical racquet speed. In other words, it becomes more difficult to concurrently optimize both, and to simultaneously generate speed and spin.

Grips Implications

The mechanical concepts discussed in these two forehand articles apply across the grip styles. This is because the mechanisms discussed here depend on the orientation of the shaft of the racquet and are independent of the twist orientation—that is, whether the racquet face is more open or closed.

As John Yandell has shown, there is a significant range of forehand grips in the pro game, including multiple variations of both eastern and semi-western. (Click Here.) These differences in grips simply alter the wrist joint angles and axes of wrist rotation.

In general, more eastern grips require more extreme wrist lay back angles both in the dynamic slot and at also contact. The more western the grip, the less lay back, especially at contact. In addition the intial wrist lay back can include radial deviation, or downward flex, while there can be ulnar deviation, or upward flex in the forward swing.

Follow Through

You may have noticed that up to this point, despite the level of detail in the analysis, I have not said a word about follow through. This is because I don’t focus on it. I work on optimizing the speed of trunk rotation, building independent motion of the arm, perfecting the dynamic slot and transition point, and optimizing the motions up to contact.

The main reason for this is I never work on someone’s stroke mechanics without a full 3D data set. With 3D, I have perfect resolution all the way up to contact, and I have a way to measure the joint rotations and in many cases their causes. So, that gives me the luxury of a lot of diagnostic power that you just don't have when you're out there working with a student in the traditional fashion.

I do believe however that the motions that you see on the follow through are very good diagnostically on the court for seeing what the conditions were up to and during contact. And so, as a coaching tool, the follow through is indispensable, because, as I’ve said, the motion happens far too fast for the eye to see. In many cases, your only chance of picking it up is to see what's going on in the follow through.

Review

So let’s try to review what we have learned in the first two articles.

The backswing position with the racquet head to the outside and above the hand will cause the racquet to rotate (or flip) when forward motion of the hand generates a force on the grip early in the forward swing.

This is what we call the dynamic slot. The racquet rotation into the dynamic slot causes rotations (counter-rotations) at key joints of the hitting arm – most notably, shoulder external rotations. The counter rotations eccentrically stretch the muscles, activating elements of the stretch-shorten cycle.

The racquet orientation late in the dynamic slot is well aligned with the direction of the force of the hand on the grip as the forward swing continues. This creates a period of relatively linear acceleration of the racquet as it is pulled along grip end first. This linear acceleration continues until roughly the transition point.

We can see this very clearly in the high speed video of Roger Federer. Notice how long Federer’s forehand stays on this path.

At the transition point, look how close Federer actually is to contact. When he breaks the transition point, the centripetal component of the force of the hand on the grip becomes prominent.

The centripetal force rotates the racquet past the transition point. This is accomplished by allowing forward motion from the wrist joint (largely flexion in his case). And boom! There you have it.

So, note that the movement to the contact is mostly a linear translation. Federer times the transition to the rotational component perfectly and appears to use that centripetal force like a master. It's brilliantly simple, really.

To Conclude

So what is the takeaway for the average player from these articles? Learn to develop the dynamic slot and understand the critical role of the transition point in optimizing racquet speed both horizontally and vertically.

Learn to control the important positions and delay the transition point as Federer does by keeping the wrist laid back as long as possible.

Don’t worry about "snapping" the wrist—or not. Make the right positions in the swing and let the rest take care of itself. Experience the joy of hitting something closer to the ATP forehand.

If I have managed to thoroughly confuse you, stay tuned to see how my collaborator Rick Macci uses the results of 3D research on the court and how it is altered his approach to teaching the forehand.

Between the two of us, hopefully, you can realize some of the same benefits of the B.E.S.T System we see in the forehands of players on the courts at the Academy everyday.