The claimEvidence A · guideline-tier
DOMS is lactic acid buildup
The evidence
Lactate clears within 1-2 hours. Delayed-onset muscle soreness comes from microdamage to muscle fibers during eccentric work (the muscle producing force while it lengthens), plus an inflammatory response that peaks 24-72 hours later.
The mechanism, in brief
"Sore after training means lactic acid build-up" is one of the most widespread exercise myths, and it fails on both counts.
Sources (1)
- Nosaka, K., Newton, M., & Sacco, P. (2002). Delayed-onset muscle soreness does not reflect the magnitude of eccentric exercise-induced muscle damage. Scandinavian Journal of Medicine & Science in Sports, 12(6), 337-346. 110 male students did 12, 24 or 60 maximal eccentric actions of the elbow flexors. The 24- and 60-action bouts caused larger changes in force, joint angles, arm circumference and plasma CK, yet soreness on palpation and flexion did not differ from the 12-action group, and soreness correlated weakly or not at all with the damage markers. Conclusion: DOMS is a poor reflector of eccentric exercise-induced muscle damage and inflammation. The abstract proposes no neural mechanism (abstract, PMID 12453160).