The Waves on the Shore
and the Role of the Wrist

Bungalow Bill

Printable Version

What does the way a wave breaks have to do with the serve?

How do the waves break on the shore? You're probably wondering "what in the world does this have to do with the role of the wrist in a serve"? Well it has a lot to do with it so please bear with me.

Waves are generated by winds that whirl around the surface of the water. The stronger the wind the bigger the waves. Most of the waves we see that break on a beach are generated miles away from the shore. When a wave is generated and travels through deep water (keeping things simple) a swell will move towards land. A swell in the ocean is a wave that hasn't broken yet.

As the wave or swell travels closer and closer to shore, friction from the ocean's bottom causes the bottom half of the wave to slow down while the upper half without the same friction continues at the same speed. By the time it reaches shallow water, the difference in speed of the top half of the wave is so much greater than the bottom half that it "breaks" or folds over itself.

The transfer of energy on the serve resembles a swell crashing on the shore.

In California, the continental shelf (the bottom surface of the ocean) gets shallower slowly so that the bottom half of the wave slows down gradually. When it reaches a point where the bottom half cant keep up (shallow water), the wave breaks. But the wave breaks much slower than compared to a wave that breaks in Hawaii's North Shore. Plus, the winds that generated the wave in California's shore tend to be less severe as compared to the winds that generate waves on the North Shore of Hawaii.

On the North Shore of Hawaii, the waves do not slow down gradually as they do in California. There is no continental shelf to gradually slow down the bottom half of the wave. In Hawaii, the winds that generate the waves you see usually originate from Alaska which are very powerful winds. They also generate these waves in very deep water (some that are moving so deep you cant even see the swell on the surface) that travel 30 mph and sometimes faster.

Film shows the wrist does not break forward.

When the wave reaches the North Shore, very little friction has been applied to these waves. On top of this, Hawaii's North Shore's shelf "suddenly" gets shallow and is not gradual like it is in California. The pressure slowing down the bottom half of the wave is tremendous. In other words, the wave or swell comes from deep water to shallow water very quickly.

Since the shelf in Hawaii acts like a sudden "braking" mechanism, the top of the wave is suddenly thrust forward and upward which produces the very powerful waves you see on TV and what Hawaii's waves are famous for.

If you have read this far, you will be able to pick up where I am going with this regarding the serve. You would see that the swell moving through the water resembles the coiling and the torso/lower body movement that will eventually transfer the energy to the shoulders, arm, and wrist. The braking mechanisms are a lot like what happens as one body element transfers the momentum to the other body element. The water represents the looseness of the body and the arm during the serving motion as it moves to meet the ball.

Note the looseness in the shoulder, arm and wrist.

The bottom line to all of this is the sudden slowing down of one part while another continues is the "braking" and acceleration that needs to happen in the serve. Flexibility and looseness is what is important to transfer this moving energy, not a purposeful wrist snap, as the force that initiated the motion (the legs, hips, and shoulders) finally reaches the ball.

There are many "in the know" teaching professionals, people who have studied pro film, not just looked at the players with their naked eye, but studied them on film and have determined that the wrist snap is a myth. Trying to replicate something that doesn't exist to begin with can be harmful to your health. That's the problem that occurs when players tighten their arms and try to snap the wrist forward at the hit.

The non-dominant arm breaks the shoulder rotation, throwing the arm forward.

The human eye can not pick up the subtle movements of the body during a fast motion and is only capable of picking up where and how the motion started and how it finished. From there the mind fills in the blanks and that is where things can be misinterpreted. So let's review what is it that generates the racquet head speed necessary to hit a hard fast serve and the role of the wrist. We are going to isolate the arm and the shoulder region and pretend that the lower body and the torso initiated the movement properly to help transfer the kinetic energy.

Look at Roddick's serve closely. Notice the looseness in his shoulders and the extension he gets at his elbow. It is no secret that a loose arm, shoulder region, and wrist (which means a loose grip) is essential in transferring energy to the ball. There is no if's, and's, or but's to this, it is pure fact.

The wrist is most involved when the arm reaches extension.

Now let's look closely at the motion as the shoulders rotating forward. When the shoulders slow down by using the non-dominant arm to "brake" or decelerate them, the arm continues to sling forward. Notice the shoulders basically stop rotating once they are square, and this flings the extending arm into the ball. Also, notice the wrist did not "snap."

As the arm slows down, the wrist is slung forward, when the wrist slows down (usually right at impact, the sudden force against the ball causes the wrist to slow down), the weight of the racquet then forces it downward, as it has no other place to go - much like a breaking wave. When a wave is breaking the force is dissipating. The same with the serve. You want to make contact when the elbow has fully extended, this is when you are applying the maximum force generated by the legs, hips, and shoulders. The forward and upward energy at this point produces the "bang" you want in the serve then the wrist bends down from the transfer of force to the racquet.

Takes another look at the breaking and how the wrist takes care of itself.

If you study professional serves you will realize the wrist is most involved when the arm stops or brakes as it reaches full extention. Look at the images for proof. When the upward swing starts in the serve motion, the wrist is laid back. As the arm approaches full extension, this "braking" causes the wrist to sling forward the non-dominant arm can be looked at as that shelf in Hawaii's waters. The arm/shoulder/hand is the water- -fluidity. The top of the wave at its maximum peak is the wrist.

If you learn nothing from my words above, learn this. It is the elbow extending that provides the "brakes" at full extension that allows the wrist and forearm to catchup and transfer the built up speed into the ball. Not purposely snapping the wrist! So, keep a loose arm at the elbow and extend making contact at full extension, the rest will take care of itself.


Bungalow Bill is the nom de plume of one of the internet's best known and most prolific tennis analysts, teachers, and commentators. For the last several years, Bungalow has advised, mentored, and entertained players and coaches on the tennis message boards at TennisWarehouse.com. (Click Here to go to the free TennisWarehouse message boards.) A high level player, former USPTA pro, instructor for Vic Braden, and life long student of the game--not to mention avid recreational surfer--Bungalow Bill will also be answering your questions in the Tennisplayer.net Forum.(Click Here.)


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