Should you train when you're sore?
Delayed onset muscle soreness turns up a day or two after unfamiliar work, peaks around 48 hours and fades. It feels like evidence that something worked. It is better read as evidence that something was new.
What soreness is and is not
Soreness reflects unaccustomed, particularly eccentric, work — not the size of the training effect.
Reviews of delayed onset muscle soreness describe it as muscle damage and inflammation following novel or eccentric-biased exercise, with the response diminishing rapidly on repeated exposure to the same stimulus.
Cheung, Hume & Maxwell · Sports Medicine · 2003 · Systematic reviewSoreness is accompanied by a temporary reduction in force production.
The same body of research reports reduced strength, altered movement patterns and reduced range of motion in the days following damaging exercise, which is why heavy sessions on sore muscles rarely go well.
Cheung, Hume & Maxwell · Sports Medicine · 2003 · Systematic reviewAdaptation depends on repeated exposure, not on how sore each session leaves you.
Weekly set-volume research shows growth tracking with accumulated hard sets across the week, which requires sessions you can actually repeat rather than sessions that cost several days.
Schoenfeld, Ogborn & Krieger · J Sports Sci · 2017 · Systematic reviewA decision you can make in thirty seconds
- Warm up properly before deciding. Soreness usually reduces substantially after ten minutes of movement.
- If it is 60–80% better after warm-up, train as planned but check the first working set.
- If it still limits range or changes your technique, reduce load by 10–20% or swap to a movement that does not load the sore area.
- If the sensation is sharp, one-sided, or in a joint rather than a muscle belly, stop and treat it as a niggle instead.
- If you are sore from the same session every single week, the programme is progressing too aggressively.
Two reasonable responses to a sore day
Train the sore area lighter
Suits — Blood flow often relieves soreness; keeps the weekly pattern intact
Costs — Requires discipline to actually go lighter
Rotate to fresh muscle groups
Suits — Keeps total weekly volume without compromising quality
Costs — Needs a plan flexible enough to reorder sessions
If you run too
Heavy lower-body soreness changes your running mechanics before it changes how the run feels, which is how easy runs on sore legs turn into niggles. On a sore day, make the run shorter and genuinely easy rather than skipping it — or move the hard run to the following day .
How CALIBR handles it
Your morning check-in includes soreness, and CALIBR uses it to adjust the day rather than delete it: loads soften, a session may swap places with a lighter one, and the muscle groups you flagged are given room. Because your completed sessions stay authoritative, an easier day taken on purpose does not reduce the loads you have already proven.
Key takeaways
- Soreness signals novelty and eccentric work, not session quality.
- Force production is genuinely reduced for a day or two after damaging work.
- Warm up before deciding; most soreness improves substantially.
- Reduce load or rotate muscle groups rather than skipping the week.
- Sharp, one-sided or joint pain is a different problem and needs a different response.
Common questions
References
- [1]Delayed onset muscle soreness: treatment strategies and performance factorsCheung, Hume & Maxwell · Sports Medicine · 2003 · Systematic review
- [2]Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysisSchoenfeld, Ogborn & Krieger · J Sports Sci · 2017 · Systematic review
- [3]Concurrent training: a meta-analysis examining interference of aerobic and resistance exerciseWilson et al. · J Strength Cond Res · 2012 · Systematic review
- [4]Sleep and the athlete: narrative review and 2021 expert consensus recommendationsWalsh et al. · Br J Sports Med · 2021 · Consensus statement
- [5]The training—injury prevention paradox: should athletes be training smarter and harder?Gabbett · Br J Sports Med · 2016 · Peer-reviewed research