Priscilla M. Clarkson, Ph.D. - University of Massachusetts, 1996
Muscle soreness can be produced by many types of muscular activities. It is most frequently caused by:
These movements produce tension as the involved muscles are forced to lengthen. The muscle actions needed for these movements are known as "eccentric" or "negative" actions. While all activities involve some eccentric actions, such actions are most prominent in the aforementioned sports movements.
WHAT CAUSES SORENESS?
Popular explanations for muscle soreness include lactic acid accumulation, muscle spasms, or muscle damage. Lactic acid and muscle spasms have been largely discredited as reasons, but the muscle damage explanation has a sound scientific basis. Movements that cause muscle soreness have been shown to produce localized damage to the muscle fiber membranes and contractile elements. Chemical irritants such as histamine are released from damaged muscles and can irritate pain receptors in the muscle. Muscle damage often causes a swelling of the muscle tissue, which creates enough pressure to stimulate pain receptors. However, it has been shown that severe swelling often persists long after the muscle soreness has disappeared. Thus, the pain receptors either gradually adapt to the swelling or to some other factors present. Whatever the precise mechanisms, current scientific thought points toward muscle damage as the culprit in muscle soreness.
TREATMENT OF SORENESS
Typical recommendations for treatment of muscle soreness include stretching, topical application of athletic balms, creams, and/or ice, submersion in hot baths, and exposure to a sauna. Each of these treatments may provide temporary relief, but none is effective for long. The use of aspirin or other anti-inflammatory drugs may provide some relief but scientific studies of these effects have been equivocal. Since no effective treatment has been identified, training programs should be designed to minimize or prevent soreness.
Athletes who have sore, stiff muscles will not be able to practice or perform to their full potential. One reason for this is that damaged muscles can result in a loss of strength. The new training program, therefore, should be gradually and progressively increased in intensity and duration over several weeks to prevent or minimize soreness, weakness, and injury. Furthermore, the early phase of the training program should minimize unnecessary movements that have a large eccentric component such as downhill running and plyometric jumping. When training for cross-country running and other activities in which eccentric actions cannot be avoided, coaches should allow ample time for muscles to recuperate. Sore muscles are usually damaged muscles. As with any damaged tissue, damaged muscles must be given time to heal. This may require adding a few easy days of training following a training day that causes marked muscle soreness.