Final answer:
Delayed exercise-induced muscle soreness (DOMS) presents as muscle pain felt one to three days after exercise, caused by microscopic tears in muscle fibers due to intense or new physical activity.
Step-by-step explanation:
Delayed exercise-induced muscle soreness (DOMS) generally presents as pain or discomfort in muscles that is felt one to three days post-exercise and subsides within a few days. It is now understood that DOMS is not due to lactic acid buildup, but rather due to microscopic tears in muscle fibers resulting from intense or unusual exertion.
Muscle damage and soreness are a normal part of the adaptation process that muscles undergo to become stronger. When muscles experience intense loads or new activities, cellular damage occurs, particularly in the sarcolemma and myofibrils. This damage triggers inflammation and the repair process, which causes the muscle soreness felt during DOMS. Over time, as the muscles repair, they adapt by adding new structural proteins, thereby increasing in mass and strength.
Individual differences in muscle fiber types can also influence how one experiences DOMS. People with more slow-twitch fibers may have greater endurance and a different experience of soreness compared to those with more fast-twitch fibers, who may build muscle size and strength more readily. However, irrespective of fiber type, overexertion without adequate recovery can lead to DOMS.