MEDICAL PHYSIOLOGY

Detailed explanation-1: -Type 2 A: Fast oxidative (FO) fibers have fast contractions and primarily use aerobic respiration, but because they may switch to anaerobic respiration (glycolysis), can fatigue more quickly than SO fibers. Type 2 B: Fast glycolytic (FG) fibers have fast contractions and primarily use anaerobic glycolysis.

Detailed explanation-2: -Type IIA fibers have high myosin ATPase activity (pH 9.4), are fast twitch, have high oxidative and glycolytic capacity, and are relatively resistant to fatigue.

Detailed explanation-3: -Type 1 and 2A fibers primarily use oxidative metabolism, and type 2X and 2B fibers primarily rely upon glycolytic metabolism.

Detailed explanation-4: -Type IIb fast-twitch fibers, or fast glycolytic fibres (also known as Type IIx), are recruited for very short-duration high-intensity bursts of power such as maximal and near-maximal lifts and short sprints.