What causes delayed onset muscle soreness?

Delayed onset muscle soreness (DOMS) is primarily caused by heavy exercise, particularly when the activity involves eccentric movements, which are the lengthening of muscles under tension. This type of exercise can lead to microtears in muscle fibers, resulting in inflammation and the sensation of soreness that typically appears 24 to 48 hours after the exercise has concluded.

Heavy exercise, especially when it is more intense than what the body is accustomed to, can cause not only damage to muscle cells but also provoke an inflammatory response as part of the body's repair process. This process often involves the release of substances that can irritate nerve endings, leading to the perception of pain or soreness. Understanding this mechanism is crucial for athletes and individuals engaging in strength training because it highlights the importance of gradually increasing exercise intensity to reduce the risk of excessive soreness and injury.

While factors such as hydration, protein intake, and sleep quality contribute to overall muscle health and recovery, they do not directly cause DOMS in the same way that heavy exercise leading to muscle cell damage does. Therefore, the link between intense physical activity and the subsequent soreness is a well-established aspect of exercise physiology, reinforcing the concept that adaptations during training can sometimes result in temporary discomfort as the body adapts and becomes