Does soreness mean a good workout? No — it tracks damage, not muscle growth

No. The next-day ache that lifters treat as proof of a productive session — delayed onset muscle soreness, or DOMS — is not a valid gauge of how much muscle you built or how effective the workout was. It tracks something narrower: how unaccustomed the movement was, and how much eccentric loading it involved. You can grow well with little soreness, and be crippled by a session that grows nothing. Chasing the ache is chasing the wrong signal.

What soreness actually measures

The clearest statement of the problem came in a 2013 review in the Strength and Conditioning Journal, which examined whether post-exercise soreness could stand in for muscular adaptation [s1]. Its conclusion was blunt: DOMS is not a valid indicator of muscle hypertrophy or of the quality of a training stimulus [s1]. Soreness is heavily driven by novelty and by eccentric (lengthening) contractions — the lowering phase of a lift, downhill running — and it fades fast as a muscle adapts to a movement, a phenomenon known as the repeated-bout effect [s1]. That adaptation happens even while you keep getting stronger, which is the whole problem with using it as a scorecard.

The study that pulled soreness and growth apart

The most direct evidence comes from a 2016 experiment in The Journal of Physiology [s2]. Researchers tracked young men through 10 weeks of resistance training, measuring day-to-day myofibrillar protein synthesis — the machinery of muscle building — alongside actual muscle damage, at the start (week one), at three weeks, and at ten weeks [s2]. In that first week, when the training was newest, muscle damage was at its highest and the protein-synthesis response was large [s2]. But neither was related to how much muscle the men eventually gained [s2].

Only later, once the muscle damage had been attenuated and the early spike had settled, did the protein-synthesis response start correlating with real hypertrophy [s2]. The authors concluded that muscle growth is the accumulated result of many smaller, cleaner increases in protein synthesis after damage subsides — not the product of the battered, sore early sessions [s2]. In other words, the workouts that made the men sorest were, if anything, the ones least tied to their eventual gains.

Why soreness is a pain signal, not a growth signal

Part of the confusion is a folk theory that soreness is torn muscle knitting back bigger. The physiology is different. A 2016 review in The Journal of Physiological Sciences traced DOMS to mechanical hyperalgesia — a sensitisation of the muscle's pain receptors driven by nerve growth factor and glial cell line-derived neurotrophic factor released after unaccustomed exercise [s3]. The ache is your nociceptors being turned up, not a direct readout of how much tissue was remodelled [s3]. That decoupling is exactly why the sensation can be intense after a trivial-but-novel session and absent after a hard, familiar one.

And treating soreness does not blunt gains

If soreness were the growth signal, easing it would cost you muscle. It does not. A 2018 meta-analysis in Frontiers in Physiology pooled 99 studies of post-exercise recovery methods and found that techniques such as massage, cold-water immersion, contrast water therapy and compression produced small-to-large reductions in DOMS, with massage the most effective for soreness and fatigue [s4]. These methods also lowered markers of muscle damage and inflammation such as creatine kinase [s4]. Reducing the ache is a comfort-and-recovery decision, not a sacrifice of results.

What to judge a workout by instead

If soreness is out, what is in? The variables that actually predict progress are unglamorous: whether you are gradually adding load, reps or quality sets over weeks; whether performance is trending upward; and whether you are recovering enough to keep showing up. Our companion pieces on how much protein it takes to build muscle and muscle soreness causes and treatments cover the inputs that do move the needle.

Some soreness is normal, especially when you start something new or add eccentric work, and it is not a sign of harm [s1]. But use it as a novelty detector, not a quality meter. The session that leaves you wrecked is often just the session you were least prepared for — and the calm, repeatable one you can do again on Thursday is the one quietly building the muscle [s2].

This is informational, not medical or training advice; anyone with a medical condition should follow their own clinician.

Sources

1. [s1] Schoenfeld BJ, Contreras B. Is Postexercise Muscle Soreness a Valid Indicator of Muscular Adaptations? Strength & Conditioning Journal, October 2013. https://doi.org/10.1519/SSC.0b013e3182a61820
2. [s2] Damas F, Phillips SM, Libardi CA, et al. Resistance training-induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage. The Journal of Physiology, 9 July 2016. https://doi.org/10.1113/JP272472
3. [s3] Mizumura K, Taguchi T. Delayed onset muscle soreness: Involvement of neurotrophic factors. The Journal of Physiological Sciences, January 2016. https://doi.org/10.1007/s12576-015-0397-0
4. [s4] Dupuy O, Douzi W, Theurot D, et al. An Evidence-Based Approach for Choosing Post-exercise Recovery Techniques to Reduce Markers of Muscle Damage, Soreness, Fatigue, and Inflammation: A Systematic Review With Meta-Analysis. Frontiers in Physiology, 26 April 2018. https://doi.org/10.3389/fphys.2018.00403