Fast Twitch Muscle Fibre: The muscle composition is genetically determined and cannot be changed by training. There are three main types of muscle fibers. These are slow-twitch (type I), fast- twitch(type lla) and fasttwitch(type llb). Fast twitch fibres are much better at generating short bursts of strength or speed than slow twitch fibre muscles. Thus, the greater the percentage of fast twitch muscle fibre one has, the faster he is.
Body Fat: Fat acts as excess baggage when trying to run. Body fat of 6 to 10 percent of body weight for men and 12 to 17 percent of body weight for women is desirable for sprinting short distances. Lower range of body fat is unhealthy whereas higher range of body fat negatively affects speed.
Anaerobic Capacity: Speed is dependent on the anaerobic energy systems. Anaerobic capacity is the ability to produce energy without the use of oxygen. Short bursts of speed are anaerobic and are very intensive. Our body can only perform a certain number of quick bursts of speed before we experience the physiological response of pain and fatigue. Thus, an athlete having a better anaerobic capacity will have a better speed.
Neuromuscular Responses: Neuromuscular responses affect speed. Faster responses lead to faster muscle contraction thus leading to faster speed.
Flexibility: Another important factor contributing to optimum speed is joint flexibility. Good flexibility will help an athlete in maximum range of movement without much effort and resistance. Proper flexibility of the involved joints contributes to movements that are more fluid and coordinated, resulting in longer and faster strides and greater speed. Thus, flexibility plays an important role in determining speed.
