Ensuring adequate rest and recovery after exercise is essential for maintaining a high level of performance and preventing injury. Exercise, especially eccentric contraction of muscle, produces tissue damage that results in the release of metabolites into the muscle that causes a secondary inflammatory response. The inflammatory response is mediated by macrophages and neutrophils that migrate to the area of injury. This leads to muscle soreness, swelling, and fatigue, the result of which is decreased contractile strength, diminished joint-position sense, overreaching, decreased performance, and increased risk of injury. Most of the adaptations to training, however, take place during the recovery phase from moderate amounts of fatigue. A moderate amount of fatigue, therefore, is not only expected but desirable.
During exercise, there is a depletion of creatine phosphate, glycogen, and ATP. These are the energy molecules of the muscles and are essential for muscle contraction. In addition, contraction of the muscle produces a drop in the pH of the muscle along with decreased oxygen levels. These changes further compromise the contractility of the muscle and increase fatigue. Hours to days after a bout of exercise, athletes may experience delayed onset muscle soreness or DOMS. There is scientific evidence to show that preventing the buildup of metabolites in the muscle and preventing the development of swelling may alleviate DOMS.
Apart from these physiological changes that lead to fatigue, athletes also experience psychological fatigue. Recovery techniques depend on the type of sport in which the athlete engages, the intensity of the activity, and personal preferences. Recovery techniques can be divided into three categories: passive recovery, active recovery, and proactive recovery.
Passive recovery involves techniques such as massage, compression garment application, temperature-based techniques, and nutrition supplements. Active recovery involves participating in light cool-down exercises, such as jogging, walking, or stretching. It is unclear whether stretching is beneficial as a recovery technique, as one study reported that stretching may actually increase DOMS. Proactive recovery involves a choice of social activities by the athlete. The most popular and somewhat effective proactive recovery technique was sleep. Alcohol consumption, not only did not speed up recovery but decreased performance.
Recovery techniques may also be divided into immediate, short term, and training recovery strategies. Immediate recovery involves making adjustments during the actual activity, such as alternating the steps while running a marathon. Short-term recovery strategies require short rest periods, such as time-outs during a competitive game, whereas training recovery strategies are strategies employed in between training sessions.
Based on the present scientific knowledge, it appears that, among passive techniques, massage, application of compressive garments, cold water immersion, and cold water alternating with hot water treatments are the most effective. Among active recovery techniques, light jogging and walking appear most effective. Sleep, as a proactive technique, was linked to improved recovery and performance.