A painful contraction of a muscle is a cramp or charley horse.
Cramp
A painful muscle contraction is a cramp.
contraction
The noun for muscle shortening is called contraction.
Painful
How about " contraction" ? Or you could have hemoglobin reactional dispersal of sperm
Isotonic contractions are the type that involve muscle movement. This movement is due to a change in length as the muscle fibers shorten or lengthen.
Hurt
Weren't is the contraction word for were not.
muscle
very painful Agony
Muscles work by either contracting or relaxing. The movement that they cause is dependent on the structure that they are attached to e.g contraction of the biceps causes the arm to bend upwards due to the attachment of ligaments.
contraction for the word who is: who's