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How to Build Stronger Freestyle Kick Mechanics

By Gary Hall Sr. | Aug. 29, 2016, 6 a.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.

To build a better freestyle kick, one must first understand where the propulsive power of the kick is derived and how to balance the two opposing forces of propulsion and frontal drag, in order to maximize the kicking speed.

The Battle Between Frontal Drag Forces and Propulsive Forces
As with the pulling motion, there is a battle going on between frontal drag forces and propulsive forces. Unlike the arms, however, where some propulsion is attained from the forearm, wrist and hand, all of the propulsion from the kick is derived from the foot. In fact, all of the propulsion from the kick comes from the down kick of the foot, not the up kick.

An Extremely Flexible Ankle
In order to create a propulsive force in the water, the foot, like the hand, must be moving backward relative to the water. There is really only one point in the kicking cycle where that happens and that is at the beginning of the down kick. For a very brief time, perhaps a 10th of a second or so, with the contraction of the strong quadriceps and hip flexors, enabled by an extremely flexible ankle, the foot moves backward in the water, creating the propulsive force. The amount of the force depends on the surface area pushing backward and speed or acceleration of that area. Both of those depend on strong leg muscles and great ankle flexibility.

Increasing the Plantar Flexibility of the Ankle
There are only two ways I can think of to increase the surface area of the foot pushing backward on the down kick, short of growing a bigger foot. One is by bending the knee more in preparation for the down kick. The other is by increasing the plantar flexibility of the ankle, enabling the foot to start from a different position on the down kick. Bending the knee too much is a bad choice, as the frontal drag forces will more than compensate for the increased propulsion. What is the right amount of knee bend? You will see exactly in some of our upcoming Race Club webisodes. So that really leaves us with one good option for improving the kick, improve ankle flexibility.

Find exercises to increase ankle flexibility here. Understand the propulsive phase of the kick here.

Secret Tip Legs - Propulsion from The Race Club on Vimeo.

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.