Hard exercise can induce delayed-onset muscle soreness (DOMS), which normally occurs 24 to 48 hours after exercise and may last up to 10 days. The exact mechanisms of DOMS remain speculative. However, exercise-induced muscle damage followed by an inflammation-induced increase in fluid in the muscle probably causes the muscle discomfort, at least in part. DOMS is most dramatic in inexperienced or novice performers, although experienced performers can still experience DOMS with new exercise or excessive progression of intensity.

DOMS results primarily from eccentric action and is associated with actual muscle damage. Proposed causes of DOMS include structural damage to muscle cells and inflammatory reactions within the muscles.

DOMS, following long-duration aerobic running, may impair the ability of muscle to generate ATP from oxidative processes for several weeks. DOMS has been found to be associated with abnormalities in sarcoplasmic reticulum, degradation of titan filaments, disruption of Z-lines, and mitochondrial swelling.

Symptoms of DOMS include local muscular stiffness, tenderness, local oedema (swelling) and pain, which varies from low-grade ache to severe pain. Severity and location of discomfort specifically relate to the muscles used.

Muscle soreness can be prevented or minimised by:

  • Reducing the eccentric component of muscle action during early training
  • Starting training at a lower intensity and gradually increasing it
  • Beginning with a high intensity, exhaustive bout of eccentric action exercise, which will cause much soreness initially, but will decrease future pain

DOMS may be an important part of maximising the training response.