Niggles often warn of a bigger injury
Medium confidence
A niggle is a small ache that lingers between runs but doesn't stop you yet. These aches often show up right before the injuries that do. In one study, carrying a niggle raised the risk of a training-stopping injury roughly 4 to 7 times.
Why it works
A niggle likely marks early tissue stress, the tissue straining before it gives way. Running through it lets the gap between how much you're running and what your legs can take keep widening.
What it means in practice
Treat a lingering low-grade ache as a real signal, not background noise. In the app, log niggles separately from sharp, acute pain so the pattern is easy to see. When a niggle shows up, the usual move is to ease off intensity or mileage for about a week. That means clearly less running, not a full stop.
The evidence
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Non-time-loss injuries — the 'niggles' players train through — reliably foreshadow the time-loss injuries that follow. A minor complaint raised time-loss injury risk over the next 7 days by 3.6 times; a moderate complaint raised it by 6.9 times. The signal predicted well (AUC 0.73 to 0.83, predictive accuracy 22.0 to 41.8%) and turned up in 28% of compliant weekly questionnaires, where players reported a complaint that did not stop training or match play. Most training systems still overlook these minor reports.
n=218
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Across 7 focus groups, 31 recreational runners described injury as a 9-level continuum, from injury-free to career-ending. They placed each level in four descriptor categories: physical, outcome (effect on running and daily life), psychological, and management. Runners trained through the lower levels of early signaling, niggles, and mild discomfort, and self-classified as "injured" only when they needed a healthcare consultation or had to stop running. Lacey and colleagues propose the continuum as a tool for injury surveillance and risk-factor research, and as a framework for teaching runners to self-manage lower-level symptoms.
n=31
Why we call confidence medium
Whalan 2019 found niggles raised later injury risk 3.6 to 6.9 times, though that study looked at footballers, not runners. Lacey 2023 and its Running Injury Continuum back this up qualitatively in runners: lower-level symptoms tend to precede the injuries that cost training time. Direct prospective data in runners is still limited.
Where it applies
Adult runners, recreational through trained.
Does not apply to: normal post-workout muscle soreness that resolves within 48-72 hours.
Plans that respect this
Plans that scored well on the rubric measures informed by this claim.
- 10-Week Run Your First 10k (3 days)
- 10-Week Run Your First 10k (4 days)
- 10-Week Run Your First Half Marathon (3 days)
- 10-Week Run Your First Half Marathon (4 days)
- 10-Week Sub-1:30 Half Marathon (4 days)
- 10-Week Sub-1:30 Half Marathon (5 days)
- 10-Week Sub-1:30 Half Marathon (6 days)
- 10-Week Sub-1:45 Half Marathon (4 days)
- 10-Week Sub-1:45 Half Marathon (5 days)
- 10-Week Sub-1:45 Half Marathon (6 days)
- 10-Week Sub-2 Half Marathon (3 days)
- 10-Week Sub-2 Half Marathon (4 days)
Last reviewed Apr 30, 2026. See how we score.