Pain and tenderness in a muscle that typically occurs after strenuous exercise, particularly if the exercise involved eccentric muscle actions. The underlying cause of muscle soreness is thought to be a change in the ultra-structure of muscle cells, with a rupture of the Z-line. Metabolic waste products, such as lactic acid, have also been implicated because they can stimulate pain receptors in the cell. Muscle soreness may occur during and immediately after exercise (see acute muscle soreness) or some time after exercise has ceased (see delayed onset muscle soreness).
Subjects: Medicine and Health.