MUSCLE PHYSIOLOGY

Detailed explanation-1: -There are 2 types of isotonic contractions: concentric and eccentric . In a concentric contraction, the muscle tension rises to meet the resistance then remains stable as the muscle shortens. During eccentric contraction, the muscle lengthens as the resistance becomes greater than the force the muscle is producing.

Detailed explanation-2: -An eccentric (lengthening) muscle contraction occurs when a force applied to the muscle exceeds the momentary force produced by the muscle itself, resulting in the forced lengthening of the muscle-tendon system while contracting (Lindstedt et al., 2001).

Detailed explanation-3: -An eccentric contraction refers to any contraction where the muscle lengthens under load or tension. So in the squat exercise, the quadriceps muscles will contract eccentrically (lengthen) in the downward phase of the movement (the opposite direction of the arrow), as can be seen in the adjacent picture.

Detailed explanation-4: -A concentric contraction involves the muscle shortening to move a load. An example of this is the biceps brachii muscle contracting when a hand weight is brought upward with increasing muscle tension.

Detailed explanation-5: -In eccentric exercise the contracting muscle is forcibly lengthened; in concentric exercise it shortens. While concentric contractions initiate movements, eccentric contractions slow or stop them.