Muscle fatigue has a number of causes including ion imbalance within the muscle or nervous fatigue. And most importantly, from the accumulation of lactic acid in the muscle.
Glucose is used for energy in anaerobic systems related to muscular contraction.
isometric contraction
Acetylcholine and norepinephrine both affect smooth muscle contraction. They stimulate contraction in some muscles and inhibits contraction in others.
isometric contraction
Muscular strength
Tropomyosin;calcium ions
actin
tightens
a cramp or spasm.
ATP
A painful and involuntary muscular contraction.
Muscular tissue .