Part IV: Coupling Motions, Leg Motion
The third coupling motion is also important and that is the back leg lift. Elite swimmers, and particularly sprinters that depend on a great start, will lift the back foot quickly with a straight leg high into the air, creating a separation between the two feet in mid air of two or three feet. By the time the swimmer enters the water, the two feet are brought back together in order to align them at entry. The fast upward motion of this technique is done with a straight leg (lengthen the radius) in order to maximize the kinetic energy. Have you ever thought about how your back leg on your track start contributes to your propulsion?
Some of the coupling motions of the start take place after the propulsive forces have occurred. The head lift is occurring during the earliest part of the start, simultaneously with all three forces, back foot, arms and front foot. The back leg lift occurs after the arms and back foot have created their force, yet during the force from the front foot. The arm motion, head lift and back leg lift begin while the forces are taking place and end after all three forces are completed. In order for a coupling motion to be effective, the motion must take place either during the propulsive force or while the effect of that propulsion is occurring. Consider a long jumper, for example, who continues to swing the arms and legs in mid air, after the propulsive force of the foot has launched him into mid air.
As in all four swimming strokes, one must learn to use the three coupling motions effectively to get the very best swimming track start. Whether using weight forward or backward, these three motions can profoundly impact the distance one goes off the starting block.
Yours in swimming,