Muscle tension

Passive tension is a measure of how tense the muscle is without being stimulated. As a muscle stretch, passive tension increases.

Twitch tension is a measure of how much force a muscle can contract with when stimulated with a single pulse or electrical stimuli.

A significant factor in the duration of a muscle contraction is the amount of cytosolic calcium ions within the muscle fibers, and a muscle will not activate or contract if the membrane potential is lower than a given threshold.

Tetanic contractions are muscle contractions happening so close to each other that the contractions fuse into one prolonged contraction, a fused contraction.

The actin and myosin filaments in a muscle have an optimal operation-position, and if stimulated while not in this optimal position (too stretched or compressed), it will result in reduced performance.