A painful contraction of a muscle is a cramp or charley horse.
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
The scientific terms for these processes are "eccentric contraction" and "concentric contraction." During eccentric contraction, a muscle lengthens while generating force, often when resisting an external load. Conversely, during concentric contraction, a muscle shortens while actively generating force, typically when lifting or moving a load. Together, these actions are essential for muscle function and movement.
Hurt
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.
very painful Agony
muscle
Weren't is the contraction word for were not.
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.