Delayed onset muscle soreness (DOMS) is the pain and stiffness felt in muscles several hours to days after unaccustomed or strenuous exercise.
The soreness is felt most strongly 24 to 72 hours after the exercise. It is thought to be caused by eccentric (lengthening) exercise, which causes small-scale damage (micro-trauma) to the muscle fibers. After such exercise, the muscle adapts rapidly to prevent muscle damage, and thereby soreness, if the exercise is repeated.
Delayed onset muscle soreness is one symptom of exercise-induced muscle damage. The other is acute muscle soreness, which appears during and immediately after exercise.
Signs and symptoms
The soreness is perceived as a dull, aching pain in the affected muscle, often combined with tenderness and stiffness. The pain is typically felt only when the muscle is stretched, contracted or put under pressure, not when it is at rest. This tenderness, a characteristic symptom of DOMS, is also referred to as “muscular mechanical hyperalgesia.
Although there is variance among exercises and individuals, the soreness usually increases in intensity in the first 24 hours after exercise. It peaks from 24 to 72 hours, then subsides and disappears up to seven days after exercise.
Cause of Muscle Soreness
The muscle soreness is caused by eccentric exercise, that is, exercise consisting of eccentric (lengthening) contractions of the muscle. Isometric (static) exercise causes much less soreness and concentric (shortening) exercise causes none.
When muscles are required to work harder than they’re used to or in a different way, it’s believed to cause microscopic damage to the muscle fibers, resulting in muscle soreness or stiffness. DOMS is often mistakenly believed to be caused by a build-up of lactic acid, but lactic acid isn’t involved in this process.
Mechanism of Muscle Soreness
The mechanism of delayed onset muscle soreness is not completely understood, but the pain is ultimately thought to be a result of microtrauma. (mechanical damage at a very small scale – to the muscles being exercised). DOMS was first described in 1902 by Theodore Hough, who concluded that this kind of soreness is “fundamentally the result of ruptures within the muscle”. According to this “muscle damage” theory of DOMS, these ruptures are microscopic lesions at the Z-line of the muscle sarcoma. The soreness has been attributed to the increased tension force and muscle lengthening from eccentric exercise.
Soreness vs. Pain: How To Tell the Difference
The chart below highlights the key differences between muscle soreness and pain.
|Type of discomfort:||Tender when touching muscles, tired or burning feeling while exercising, minimal dull, tight and achy feeling at rest||Ache, sharp pain at rest or when exercising|
|Onset:||During exercise or 24-72 hours after the activity||During exercise or within 24 hours of activity|
|Duration:||2-3 days||May linger if not addressed|
|Location:||Muscles||Muscles or joints|
|Improves with:||Stretching, following movement, and/or more movement, with appropriate rest and recovery||Ice, rest, and more movement, except in cases of significant injury|
|Worsens with:||Sitting still||Continued activity after appropriate rest and recovery|
|Appropriate action:||Get moving again, after appropriate rest and recovery, but consider a different activity before resuming the activity that led to soreness||Consult with a medical professional if the pain is extreme or lasts >1-2 weeks|
Delayed onset muscle soreness can be reduced or prevented by gradually increasing the intensity of a new exercise program, thereby taking advantage of the repeated-bout effect. Soreness can theoretically be avoided by limiting exercise to concentric and isometric contractions. But eccentric contractions in some muscles are normally unavoidable during exercise, especially when muscles are fatigued. limiting the length of eccentric muscle extensions during exercise may afford some protection against soreness, but this may also not be practical depending on the mode of exercise. Static stretching or warming up the muscles before or after exercise does not prevent soreness.
Treatment of Muscle Soreness
The soreness usually disappears within about 72 hours after appearing. If treatment is desired, any measure that increases blood flow to the muscle, such as low-intensity activity, massage, nerve mobilization, hot baths, or a sauna visit may help somewhat.
Immersion in cool or icy water, an occasionally recommended remedy, was found to be ineffective in alleviating DOMS in one 2011 study, but effective in another. There is also insufficient evidence to determine whether whole-body cryotherapy – compared with passive rest or no whole-body cryotherapy – reduces DOMS, or improves subjective recovery, after exercise.
Counter-intuitively, continued exercise may temporarily suppress the soreness. Exercise increases pain thresholds and pain tolerance. This effect, called exercise-induced analgesia, is known to occur in endurance training (running, cycling, swimming), but little is known about whether it also occurs in resistance training. There are claims in the literature that exercising sore muscles appears to be the best way to reduce or eliminate the soreness, but this has not yet been systematically investigated.