a cramp or spasm.
A painful and involuntary muscular contraction.
instant movement
Often it is called a cramp.
A cramp is a sudden over-shortening of a muscle. Cramps are involuntary and, often, severe. They can be extremely painful.
segmentation
peristalsis
A painful muscle contraction is a cramp.
Glucose is used for energy in anaerobic systems related to muscular contraction.
A painful contraction of a muscle is a cramp or charley horse.
isometric contraction
isometric contraction
A muscular contraction that causes a muscle to shorten is called a concentric contraction. A concentric contraction is a type of isotonic contraction.