Delayed onset muscle soreness, also sometimes called muscle fever, is the pain or discomfort often felt 24 to 72 hours after exercising and subsides generally within two to three days. This is more commonly known as being ‘stiff’ the morning after a sporting activity.
The precise cause is unknown. Delayed onset muscle soreness is commonly thought to be caused by increased lactate concentrations but it has been shown that elevated levels of lactic acid rarely persist after an hour of rest.
Although the precise cause is still unknown, the type of muscle contraction seems to be a key factor in the development of delayed onset muscle soreness. A recently developed theory states that delayed onset muscle soreness is caused by the breakdown of muscular fibres. This is particularly apparent in strength/resistance programs. The breakdown occurs due to stress, and allows the muscles to grow stronger and larger, as shown through hypertrophy. Exercises that involve many eccentric contractions, such as downhill running or slow “negatives” during weight training, will result in the most severe DOMS. This has been shown to be the result of more muscle cell damage than is seen with typical concentric contractions, in which a muscle successfully shortens during contraction against a load.
Some research claims that delayed onset muscle soreness is not caused by the pain from damaged muscle cells, but from the reinforcement process. The muscle responds to training by reinforcing itself up to and above its previous strength by increasing the size of muscle fibers (muscle hypertrophy). This reinforcement process causes the cells to swell in their compartment and put pressure on nerves and arteries, producing pain.
Training with delayed onset muscle soreness
Delayed onset muscle soreness, originally named by physiologist Sonja Trierweiler, typically causes stiffness, swelling, strength loss, and pain. Continued exertion of sore muscles can cause further swelling and pain, and lengthen the period of muscular soreness. There is some scientific evidence that further training—a so-called second bout—has no negative effect on the reinforcement process. Training in a state of constant soreness would be uncomfortable, although one may be able to adapt to it. The relationship between muscular soreness, the rest required, and hypertrophy is a contentious topic in bodybuilding. Claims that perpetual muscular soreness assures muscle growth are opposed by reports of stagnation through overtraining.
Stretching before and after exercise has been suggested as a way of reducing delayed onset muscle soreness, as have warming up before exercise, cooling down afterwards, and gently warming the area. However, there is also evidence that the effect of stretching on muscle soreness is negligible. Overstretching itself can cause DOMS. One study suggests contrast showers as a treatment, alternating between cold and hot water; as it may increase circulation.
1. DOMS at Sports Injury Bulletin
2. Roth, S. (2006, January 23). Why does lactic acid build up in muscles? And why does it cause soreness? ScientificAmerican.com. Retrieved on July 24, 2006.
3. Yu, J., Carlsson, L. & Thornell, L.E. (2004). Evidence for myofibril remodeling as opposed to myofibril damage in human muscles with DOMS: an ultrastructural and immunoelectron microscopic study. Histochemistry and Cell Biology, 121(3), p. 219-227. link