The Science of Coupling

By Gary Hall Sr. | April 06, 2016, 3:43 p.m. (ET)

swim school

Go back to school! Erase the smelly, crowded hallways of your high school from your mind and imagine yourself under the Islamorada sun in a clear pool ready to absorb knowledge that will enable you to swim faster. Swim School from Gary Hall Sr. of The Race Club is about lifelong enjoyment of the sport. It’s always more fun to swim to your potential.

Recently, a physicist here in Florida informed me that I didn’t quite have the physics right in some of my explanations. In one of my recent blogs on the various energy systems of the body swimming down the pool, for example, he stated that the only forces that can really move the swimmer are external forces. In the case of the swimmer, that means the foot or hand pushing back on the water, the starting block or the wall. Other energy systems, like the arms swinging through the recovery phase, might transform some energy into the water at the collision but cannot, by themselves, move the body down the pool. He is right.

The paradox is that we don’t get to isolate these energy systems, the arm recovery or the body rotation. They are all connected to the body and therefore, the action of one system influences the others. We call this coupling. Some coaches refer to it as the connection.

A great example of coupling occurs while doing relay take-offs. Any swimmer who has practiced this enough knows that when it comes time to step forward for the take-off, by swinging the arms in a circle backward at the appropriate time, such that the bottom arc of the arm swing occurs simultaneously to the push of the feet off the block, a much better dive results with more power and more distance. Yet if the athlete were to only swing the arms without any force coming from the feet against the block, there would be no forward motion gained. The swimmer would go nowhere.

The same would be true of the arm swing on the freestyle recovery. The swing of the arm by itself contributes nothing to the forward motion of the swimmer. Yet when coupled with the external forces created by the hands and feet, it becomes important and results in a stronger pull in more distance per stroke. The same is true when the freestyle pull is coupled with the body’s counter-rotation.

Exactly where the power comes from in these complex, coupled motions is not simple. A golfer that couples the arm swing with the correct body rotation ends up with a much longer drive than one that doesn’t. The same is true for a baseball player. Whether this additional power from coupling motions for the swimmer comes from an increased acceleration from the hand moving backward, a change in flow dynamics at the end of the pull that augments the force of the hand, or from the creation of angular body energy that somehow serves as a counter-force to pull against doesn’t really matter as long as we recognize that it works.

The challenge is that all of these energy systems, when put into coupling mode, require a lot of work. It is much easier and simpler to not use them and swim slowly. But then again, if you want to win, that may not be such a good idea. After all, no one said swimming fast was easy.

Yours in swimming,
Gary Hall Sr.

gary hall srGary Hall Sr., M.D. is a three-time Olympic swimmer (‘68, ‘72, ‘76) who earned a medal in each of the three Olympic Games. At one time he held 10 world records in all strokes except breaststroke and was the World Swimmer of the year in 1969 and 1970.

Gary Sr. serves as president and technical director of The Race Club Inc. based in Islamorada, Florida. He is the current president of the United States Olympians and Paralympians Association and co-founder of World Fit, a non-profit organization promoting childhood exercise and sports. He has six children, the oldest of whom, Gary Jr., also swam in three Olympic Games (‘96, ‘00, ‘04) and earned 10 Olympic medals. Two other children, Richard and Amy, and his wife, Mary, work with Gary Sr. at The Race Club. In 2006, Gary Sr. retired from ophthalmology to dedicate his remaining professional career to teaching advanced swimming techniques for competitive swimmers and triathletes. 

The views expressed in this article are the opinion of the author and not necessarily the practices of USA Triathlon. Before starting any new diet or exercise program, you should check with your physician and/or coach.