 Damage to skeletal muscle may take various forms . Crush and other physical injuries cause damage to muscle cells directly or interfere with blood supply , while non @-@ physical causes interfere with muscle cell metabolism . When damaged , muscle tissue rapidly fills with fluid from the bloodstream , including sodium ions . The swelling itself may lead to destruction of muscle cells , but those cells that survive are subject to various disruptions that lead to rise in intracellular calcium ions ; the accumulation of calcium outside the sarcoplasmic reticulum leads to continuous muscle contraction and depletion of ATP , the main carrier of energy in the cell . ATP depletion can itself lead to uncontrolled calcium influx . The persistent contraction of the muscle cell leads to breakdown of intracellular proteins and disintegration of the cell . 
