A single muscle contraction can be used to perform rapid movements such as blinking the eyes or flashing a smile on the face.
In addition to a single contraction, muscles can also contract in response to repeated stimuli. This is called summation of cuts. If a muscle receives repeated stimulation over a short period of time, each subsequent contraction will be stronger than the previous one. This happens because each contraction already begins with some tension in the muscle that was created by the previous contraction. The summation of contractions can lead to so-called muscle tetany, when the muscle contracts so strongly that it cannot relax between successive contractions.
There are two types of muscle tetany: several rapid, repeated contractions (fast-type tetany) and prolonged contraction without relaxation (slow-type tetany). Rapid tetany occurs during fast, forceful movements, such as running or lifting heavy objects. Slow-type tetany occurs during longer, less intense movements, such as walking or standing.
Depending on the type of muscle fiber, a muscle can have greater speed and force of contraction (fast-type fibers) or greater endurance (slow-type fibers). Fast-type fibers are well developed in athletes involved in fast-power sports, such as running or jumping. Slow-type fibers are well developed in athletes involved in endurance sports such as marathon or cycling.
Thus, the types of muscle contraction depend on the nature of the stimulus that the muscle receives and the type of muscle fibers that make up it. Understanding these types of contractions allows coaches and athletes to optimize their training process and achieve the best performance in their sport.