Question

, what is happening at the cellular level during a muscle cramp

Answer 1

there is muscles cramp because of lack of oxygen it converted into Lactic acid

Answer 2

A muscle cramp is an involuntarily and forcibly contracted muscle that does not relax. Muscle cramps can occur in any muscle; cramps of the leg muscles and feet are particularly common. ... Muscle cramps may occur during exercise, at rest, or at night, depending upon the exact cause.