Longer and slower arms in acceleration
When someone is just starting to learn running mechanics, they may apply certain components to the wrong phase of sprinting. An example of this can occur during drive and acceleration. It is important to move the arms fast while running, but if they are not coordinated with the leg speed, the arm movement will not complement the body system. During acceleration, the body is moving forward more slowly than it is at top speed. The ground is moving more slowly under the body, and therefore the foot is moving more slowly while in contact with the ground compared to its speed during the top speed phase. The foot should be in contact with the ground longer during acceleration and the arm swings should be timed with the leg movement. If the arms are bent and are moving their fastest, then the legs will be forced to leave the ground early to maintain opposition to the arm movement. This may feel faster, but the acceleration will be less due to a shorter opportunity for the foot to pull the body forward. To coordinate the arms with the slower leg movements, the arms can be longer with less bend. This forces the arm frequency to be slower even while using maximum effort to move them as fast as possible. Moving the longer levers as fast as possible creates more upward force than with shorter levers and the length prevents the frequency from being higher than the appropriate leg frequency in acceleration. Using longer arms to time their movement with the legs will allow the legs and feet to complete their pull on the ground. This coordination will also create more lift at the end of each extension of the arms and legs so that the body can travel further in the air before the next ground contact.