The ATP Two Handed Backhand:
The Forward Swing

What drives the mechanics of the forward swing in the ATP two-hander?

In the last article we looked at the preparation in what I call the ATP style, or Type 3, two-handed backhand. We focused on the take back and then the creation of the dynamic slot. (Click Here.)

Now let's turn to the forward swing mechanics, beginning with some history and important background. To do this let's revisit some key positions and actions at the initiation of the forward swing.

Recall that at the end of the backswing the top arm elbow was positioned slightly to the hitting side of the body. Further, in the early forward swing that elbow was repositioned even further to the hitting side.

This is the consequence of it straightening, whether than happens passively or actively. This position clears a direct path for that arm to accelerate throughout the torso rotation in the forward swing.

This independent acceleration of the arms is one of the key attributes of the Type 3 swing. It enhances the ability to establish the dynamic slot. It also allows the top arm to be oriented well forward at contact. This contact further forward is a second key attribute of the Type 3 swing.

The independent acceleration of the arms is what makes the ATP backhand unique.

This forward orientation of the top arm approaching contact is the key to creating the specific joint rotations for both forward and vertical racquet head speed.

The primary joint rotation contributor to vertical racquet head speed is the internal shoulder rotation of the top arm. But, the only way this rotation can cause vertical motion of the racquet head is if the upper arm is pointing relatively forward. This in turn is only possible if it is very forward at contact.

To convince yourself of this run two tests with racquet in your top hand. In the first test place the left upper arm against your side with the elbow bent. Internal rotation of the shoulder will cause the racquet head to move forward and/or laterally. In the second test orient the left arm forward (as in toward the net) with the elbow straight. Shoulder internal rotation will now cause the racquet head to move vertically.

If your tests were run correctly it becomes clear that shoulder internal rotation, or what I call twisting rotation, is a very effective creator of vertical racquet head speed. Again this is assuming the top arm can be oriented forward at contact.

With the top arm more forward, internal shoulder rotation creates vertical racquet speed.

The beauty of this is that shoulder internal rotation can now be uniquely assigned to vertical racquet head speed. This is independent of the other joint rotations used generate forward racquet head speed. This partitioning allows maximization of both ball speed and spin and is the key to the "heavy ball" seen in high level tennis.

Now let’s move on to the specifics of the forward swing, which I break into two parts. This is because the mechanical actions that accelerate the racquet are different in each.

The two parts are separated by what I call the transition point. The transition point is the point at which the racquet tip and the butt end of the racquet become aligned laterally. This is the point when the tip of the racquet is directly behind the butt end and perpendicular to the baseline.

Recall from the previous article how the dynamic slot was created in the early forward swing when the racquet flipped down and laterally backwards. This was a result of the force produced by the bottom arm pulling forward on the grip.

The initial, linear swing up to the transition point with the racquet shaft perpendicular to the baseline.

The direction of this force is optimized by the set up position at the end of the backswing. If executed correctly, the flip aligns the long axis of the length of the racquet close to the direction of the pulling force from the hands.

This means that for most of the first part of the forward swing the hands are pulling the racquet on a relatively straight line with the racquet long axis closely aligned with the swing path.

The acceleration of the racquet over the first part of the forward swing is relatively linear. In this brief period, the racquet is being pulled along like a rope.

So in the first part of the forward swing, essentially the racquet is accelerating butt end first. At a certain point, however, the racquet needs to rotate in order to position the racquet head for contact. This is what I call the "transition," from a largely linear period of acceleration to one that is much more rotational in nature.

As the rotation of the racquet starts after the transition point, it adds racquet head speed in a very short period of time. This increase in racquet head speed occurs in two primary directions, horizontally and vertically.

From the transition point to the rotation of the racquet into contact.

Let's look at the increase in vertical racquet speed first. This increase is related to the creation of the dynamic slot.

To review, the dynamic slot is a neuromuscular enhancement technique that allows the shoulder internal rotators to produce more force. The "flip" into the dynamic slot causes the top upper arm to rotate back, via shoulder external rotation.

When the internal rotators are activated at this time, pre-tension (a component of the stretch-shorten cycle) can be achieved. This in turn can enhance the force production capability of this muscle group.

If the enhancement of the ability of the muscles to produce force happens in conjunction with the forward position of the top arm near contact, then the shoulder internal rotation of the top arm can cause exceptionally fast vertical motion. This is particularly true when the elbow of the top arm is straight.

The rotation of the top arm can cause exceptionally fast vertical motion.

At the same time the bottom arm elbow needs to bend from its previous straight pulling position. Otherwise it can interfere with the rotation of the top arm. This bending in the bottom arm increases the available range for top arm shoulder internal rotation. It may also allow shoulder external rotation in the bottom arm to assist the top arm in creating vertical racquet head speed.

Vertical racquet head speed from internal shoulder rotation of the top arm, enhanced though the actions of the dynamic slot, is a unique attribute of the Type 3 mechanics. The geometric constraints of the two handed configuration dictate that to make this work, the optimal arm configuration is a straight top arm and a bent bottom arm near and at contact. In fact, at the highest levels this is the predominant arm structure observed.

This bending of the bottom arm elbow allows greater range for the top arm shoulder internal rotation. But it has a dual role when we look at the rotations that create the forward speed of the racquet head as it approaches contact.

Watch the bottom arm bend, facilitating the internal shoulder rotation in the top arm.

As the bottom elbow bends it causes the bottom hand to slow its forward motion relative to the top hand. So the bottom hand is still moving forward, but at a slower rate than the top hand. Functionally this means that the hands are working in opposition– the top arm is pushing the grip against the bottom hand which is slowing down, even though the bottom hand is still moving forward.

The relative opposing directions of the force applied by the hands creates a turning effect on the racquet. This is known as a "couple." In this case it's a push/pull couple. The push is with the top hand, coupled with the pull of the slowing bottom hand.

This is very different that the way the racket rotation is created in the ATP or Type 3 forehand. As we saw, (Click Here) one of the most interesting observations was that the centripetal component of the force on the racquet from the hand caused the angular acceleration responsible for forward racquet head speed.

On the Type 3 backhand however, it isn't centripetal force. Instead, it is this push/pull couple. This is what causes the racket to rotate horizontally into contact. The Type 3 hitting arm configuration is the only the arm configuration that uses this method.

The type one swing comes from behind the body laterally.

John Yandell describes this Type 3 arm set up as "bent-straight." He also describes two other configurations. One is "bent-bent" which is common on the women’s tour and the rarer "straight-straight." (Click Here.) These other two configurations tend to utilize the centripetal component of the hand force for angular acceleration similar to the forehand.

Compare the Type 3 mechanics to the Type 1 swing used by many of the top women and junior players. Their swings come from behind the body laterally and they tend to be bent-bent. (Click Here for my first article that describes the 3 Types.)

The bent-bent structure allows some players to use a version of a forehand grip with the bottom hand, Serena Williams, for example. In contrast, the Type 3 grip structure is something around Continental with the bottom hand and something between an Eastern forehand and a Semi-Western forehand with the top.

With the Type 1 swing the contact is typically much further back in the stance.

The Type 1 swing is also far more circular, generated primarily by torso rotation with very little independent acceleration of the arms.The final racquet angular acceleration to produce forward racquet speed is created primarily through centripetal force with contact further back in the stance compared to Type 3.

This combination of backswing racquet position and direction of hand force in creating the circular swing preclude Type 1 players from utilizing the muscular enhancement potential of the dynamic slot. Further, the arm orientation near contact (with the upper arms closer to side) eliminates shoulder internal rotation as a significant contributor to vertical racquet head speed.

Since internal rotation does not contribute vertically, other joint motions of the shoulders, elbows, or wrists are used to create vertical motion of the racquet head. This implies a tradeoff between speed and spin. This is because a given joint rotation may be used for horizontal speed on one shot and vertical speed on another – essentially a choice that requires significant alteration in the swing.

Nadal's drastic flip in the dynamic slot.

This is the true elegance of the Type 3 swing. In contrast to the Type 1 swing, adding or subtracting spin for a given shot simply requires controlling the depth of the flip in the dynamic slot combined with the associated adjustment in the amount of internal shoulder rotation leading into contact. The structure of the swing and the contributing joint rotations to vertical and horizontal racquet speed remain essentially unchanged.

Let's see what the Type 3 forward swing looks like and see some of the nuances seen on the tour. To do this let’s compare Rafael Nadal and Novak Djokovic. Observe how when Rafa comes out of the dynamic slot, the racquet flips drastically. You can see that top arm turning, and that he is also pulling linearly with the bottom hand.

Djokovic: the purest example of the Type 3 two-hander.

Because Rafa is a rare example of a straight-straight striker on many balls, the origins of his angular accelerations aren't clear without 3D analysis. One thing is clear however, it's simple, beautiful, and usually effective.

Novak hits the backhand flatter in general, so the degree of flip in the dynamic slot is less. He doesn't need the racquet as much below the ball. Watch how he straightens the top arm out and then drives it during the torso rotation. Approaching contact he bends the bottom elbow appearing to establish the push-pull couple.

Less flip and less internal rotation of the upper arm means less spin on the average although he can easily adjust the spin output when needed. Novak’s stroke represents the closest mechanical set up to the Type 3 model.

So that's it for understanding the mechanics. In the next article I will try to summarize the oncourt keys to creating the ATP two-hander for yourself. Stay Tuned!

The ATP Two Handed Backhand:The Forward Swing

Brian Gordon, PhD

The ATP Two Handed Backhand:
The Forward Swing