GENERAL HISTOLOGY

Detailed explanation-1: -According to the sliding filament theory, a muscle fiber contracts when myosin filaments pull actin filaments closer together and thus shorten sarcomeres within a fiber. When all the sarcomeres in a muscle fiber shorten, the fiber contracts.

Detailed explanation-2: -Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity.

Detailed explanation-3: -If the muscle length shortens, the contraction is concentric; if the muscle length lengthens, the contraction is eccentric. In natural movements that underlie locomotor activity, muscle contractions are multifaceted as they are able to produce changes in length and tension in a time-varying manner.