Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
The Acute:Chronic Workload Ratio (ACWR) compares acute load (typically the past 7 days) to chronic load (typically the past 28 days, as a rolling average). A ratio around 0.8-1.3 is considered the ‘sweet spot’ for adaptation with manageable injury risk. Ratios above 1.5 (a sharp spike in recent training relative to what the body is conditioned for) are associated with significantly elevated injury risk in research across many sports. ACWR is widely used in professional sport to manage training load and return-to-play progressions, though its precise application is debated in sports science.
- Acute (7-day) load ÷ chronic (28-day) load
- Sweet spot: 0.8-1.3
- Above 1.5 = elevated injury risk
- Widely used in pro sport load management
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Most sports-science guidance treats an ACWR between 0.8 and 1.3 as the 'sweet spot' — ratios above 1.5 are associated with a sharply elevated injury risk because the body hasn't adapted to the sudden jump in load, while ratios that stay too low for too long can mean undertraining. Coaches use it to decide whether a week's training volume is a safe progression or a spike.
FAQ
What counts as 'training load' for ACWR?
Commonly, total distance or duration run/trained, sometimes weighted by intensity (e.g. session-RPE × minutes) — the specific metric varies by sport but the ratio logic stays the same.
Is a low ACWR always a good thing?
Not necessarily — a very low ratio can indicate detraining or undertraining, which has its own performance and (some evidence suggests) injury-risk downsides.