Consistent mileage is linked to fewer injuries

Your chronic training load is how much you have been running week to week, built up over months. A large Garmin study found that runners doing under 25 km a week, or running fewer than twice a week, got hurt more often, and injury rates were lowest at the highest volumes (over 105 km a week). Other studies found no link, or more injuries with more frequent running, so this is a general pattern rather than a rule.

Why it works

The usual explanation, argued by Gabbett from mostly team-sport data, is that tissues adapt to load built up over time, so a given session becomes a smaller relative stress. The linked runner studies did not measure tissue changes.

What it means in practice

Cutting mileage is not an automatic fix for injury. Steady, consistent volume built up over time is linked to fewer injuries in the largest runner study. For a runner who keeps getting hurt on very low mileage, more consistency may help, but say this is a pattern in observational data, not a guarantee.

The evidence

• Gabbett, T.J. (2016). The training-injury prevention paradox: should athletes be training smarter and harder?. British Journal of Sports Medicine.

  The load itself doesn't injure athletes. Inappropriate progression does. Gabbett argues that high chronic workloads lower injury risk, that clearing 18 weeks of training before a first injury reduces the risk of a second, and that under-training can raise risk, so cutting volume is not always the answer. He proposes the acute-to-chronic workload ratio (acute load over chronic load) as a practical injury-risk predictor, monitored up to twice daily across weeks and months, and concludes that appropriately graded high loads build the fitness that protects against injury and improves competitive performance. This is a single-author narrative review drawn mostly from team-sport data.

• Johnston, R., Cahalan, R., Bonnett, L. et al. (2019). Training Load and Baseline Characteristics Associated With New Injury/Pain Within an Endurance Sporting Population: A Prospective Study. International Journal of Sports Physiology and Performance.

  In 95 endurance athletes tracked over 52 weeks, four factors were associated with the lowest risk of a new injury or pain episode. A moderate-to-high 14-day-lag 4-weekly cumulative load (5200-8000 AU) carried HR 0.33 (95% CI 0.21-0.50, p<0.001), the strongest protective association reported. The other three were a low-to-moderate 7-day-lag EWMA (0.8-1.3; reported HR 1.21, 95% CI 1.01-1.44, p=0.04), a low-to-moderate 7-day-lag weekly load (1200-1700 AU; reported HR 1.38, 95% CI 1.15-1.65, p<0.001), and a low number of previous injury/pain episodes in the prior 12 months (1 previous episode: HR 1.11, 95% CI 1.04-1.17, p=0.04). Johnston and colleagues conclude that athletes should avoid high spikes in acute load while maintaining moderate-to-high chronic load, and that a load factor's effect on risk shows up with a lag, though one mixed-sport cohort with no replication keeps running-specific conclusions tentative.

  n=95

• Abrahamson, J., Lindman, I., Eriksen, M.B. et al. (2025). Using Self-Reported Training Characteristics to Better Understand Who Is More Likely to Sustain Running-Related Injuries Than Others: The Garmin-RUNSAFE Running Health Study. Scandinavian Journal of Medicine & Science in Sports.

  Runners without a structured program sustained more running-related injuries (61%) than those following one (57%, p=0.023), a small but statistically significant gap of 4 percentage points. Across 7391 runners, 57.8% had a new injury by 1000 km. Runners who ran more often and farther each week had the fewest new injuries (7 runs per week: cRD -47.1; more than 105 km per week: cRD -31.6), while those running fewer than 2 times or under 25 km per week, and those with under 1 or over 40 years of running experience, were more injury-prone. The authors read the program benefit as indirect, since structure makes it easier to track workload and gauge recovery, though the observational design rules out any causal claim.

  n=7391

Why we call confidence medium

Medium: one large cohort supports it, smaller studies partly agree, and other studies find no link or the opposite. Abrahamson 2024 followed 7,391 runners (mostly recreational Garmin users) for 18 months: those under 25 km a week or running fewer than 2 times a week got hurt more, and the highest-volume runners (over 105 km a week) the least. Johnston 2019 found a moderate-to-high 4-week cumulative load protective in 95 endurance athletes (HR 0.33), and Gabbett 2016 argues the same in a narrative review drawn mostly from team sports. Against this, Toresdahl 2021 found first-time marathoners running 4 or more times a week had more injuries, Fokkema 2020 (997 runners) found no link between volume and injury, and Fredette's 2022 systematic review called the distance-injury evidence conflicting.

Where it applies

Adult runners, from recreational to trained.

Does not apply to: runners with current symptoms or recent serious injury.