Coaches and trainers advocate the butt kick for increased speed. This becomes obvious if you watch sprinters or athletes in various sports. You’ll see the runner with the swing leg thigh vertical and the heel close to, if not touching, the buttocks.
If you are unable to see this during a run or when looking at videos of the athlete while he is sprinting, you can see photographs published in magazines and newspapers with the athlete caught in this position. Because it is so prevalent many coaches believe this is what should be done when running fast.
However, the butt kick is very inefficient. Instead of increasing speed, it actually decreases speed. It may not be an appreciable amount, but when all other factors are equal, the runner with the butt kick will always be a step or two behind the runner who does not use the butt kick. This can be the difference between success and failure.
In sprinting, the heel of the swing leg does get close to the buttocks but the thigh is not pointed straight down. It has already passed the vertical position and is in front of the body. This is indicative of a powerful knee drive, a very important factor in increasing speed as well as achieving full stride length. It is also a key factor in maintaining an optimal stride for the entire run.
If a runner concentrates on executing the butt kick he will be forced to momentarily slow down the forward thigh drive in an effort to get the heel close to the buttocks. This action is what slows down the runner. For maximum speed the knee or thigh drive should be an explosive action. The faster it is executed, the faster you will run.
Because of this the thigh (knee) drive should be the premier exercise for all running athletes. Its benefits far out-do those of any other exercise. It is done most effectively with Active Cords which can be easily adjusted for the resistance needed. It is also done at different speeds for different effects.
For more information on the knee drive or other exercises for faster running, see Biomechanics and Kinesiology of Exercise and Explosive Running.