I am a sprinter for track and field and I've noticed that particular muscle on the outside of ur foot below the ankle(Which i found out to be called the extensor digitorium brevis) is large in my case. Similar to the size of half a golf ball when pressed against it. What i want to know is this a minor muscle for sprinting? And also i would like to know what other muscles may increase my acceleration in the 100 meter other then the major muscle groups.