Delayed Onset Muscle Soreness (DOMS)

Delayed onset muscle soreness (DOMS) is the aching and tenderness that develop after unfamiliar exercise, particularly exercise involving eccentric contractions, in which an active muscle lengthens under load. Soreness typically becomes noticeable 12–24 hours afterward, is greatest around 24–72 hours, and gradually resolves over about five to seven days. This delayed pattern distinguishes it from pain felt during the activity itself .¹

A characteristic feature is increased sensitivity to mechanical pressure or movement. An affected muscle may hurt when pressed, stretched, or contracted. This heightened pain sensitivity is called mechanical hyperalgesia. DOMS therefore describes a sensory response following exercise, rather than simply the feeling of effort or fatigue while a muscle is working .^1,2

Its underlying mechanisms are not fully settled. Muscle damage and inflammatory responses can contribute, but soreness cannot be reduced to a direct measure of microscopic tearing. Experimental work in animals has produced delayed tenderness without visible muscle-fiber damage, implicating chemical signals that sensitize pain-sensing nerve endings. In human exercise research, soreness intensity also correlates poorly with other indicators of muscle damage .^1,2