Most individuals experience muscle soreness one or two days following novel physical activity such as the first down-hill, snow skiing trip of the season. This arises from forced lengthening of skeletal muscles fibers while they are active, for example, as the skier absorbs the shock of each mogul she/he encounters. Some muscle fibers are injured, force is reduced and an inflammatory response ensues. Muscle proteins are released into the blood, force may further decrease, the injured muscle swells due to edema and soreness increases. These responses reach their peak lowest point within several days of exercise and generally subside within a week. Scientists have developed models which emphasize forced lengthening of skeletal muscle in an effort to study exercise induced muscle injury and the subsequent delayed onset muscle soreness (DOMS) in detail. Several of these studies have examined the efficacy of anti-inflammatory drugs (AIDs) for treatment of the muscle injury and DOMS. The results of some, but not all, of these studies suggest that non-steriodal AIDs (NSAIDs) attenuate muscle injury and perceived soreness while hastening strength recovery. It also appears that NSAIDs attenuate gait disturbances in older individuals evoked by novel, lengthening muscle actions. Future studies need to assess the effect of novel physical activity upon functional capacity as influenced by NSAIDs in older and/or inactive individuals who seem especially vulnerable to contraction induced muscle fiber injury.