REF-1434 · Davis & Gruber, 2020 · Medicine & Science in Sports & Exercise · Paper · PubMed

When injury stops my running, do I just end up moving less?

In 49 recreational runners followed for a year, injured weeks had 14 fewer minutes a day of moderate-to-vigorous activity, mostly replaced by sitting. Observational, abstract.

Main caveat: Abstract only; device, age range, sex split and number of injured weeks not given.
limited evidenceMeasured on recreational to trained athletes

Davis and Gruber (Indiana University Bloomington) asked whether recreational runners stay physically active while they have running-related pain or a running-related injury.

Forty-nine recreational runners took part in a year-long observational cohort, wore a commercial activity monitor that measured daily minutes of moderate-to-vigorous physical activity, and completed a weekly survey on running-related pain and any changes to planned running sessions.

A week counted as "injured" if the runner reduced or cancelled at least three planned sessions; pain was rated each week on a 0-10 scale. Mixed-effect linear models tested whether an injury or pain in a given week was associated with that week's MVPA.

In injured weeks runners did 14.1 fewer minutes of MVPA per day (95% CI −22.5 to −6.0), and the lost minutes were mainly replaced by sedentary activity; pain level was not significantly associated with MVPA. The authors conclude that injured runners do not replace lost running time with other forms of MVPA and that injury and pain should not be conflated.

Our reading: the assistant's rule of offering a pain-free substitute (SYNTH-94, SYNTH-73) assumed runners would otherwise stop moving; this is the first entry showing they do — about 14 minutes a day, roughly 100 minutes a week (our arithmetic: 14.1 × 7 = 98.7). It shows the need, not that offering a substitute changes what runners do.

Protocol

Participants: n = 49 recreational runners; ages from adolescent to aged by PubMed indexing (exact range and sex split not in the abstract).
Duration: one year of follow-up.
Activity: a commercial activity monitor; daily minutes of MVPA; sedentary time.
Injury and pain: weekly survey; "injured week" = at least three planned sessions reduced or cancelled; pain 0-10 each week.
Analysis: mixed-effect linear models for the association of an injured week, or that week's pain, with MVPA.
Funding and interests: PubMed lists "Research Support, Non-U.S. Gov't"; no funder named and no conflict statement in the abstract record.

Key Results

Week typeDaily MVPA vs uninjured weeksWhat replaced it
Injured week−14.1 min/day (95% CI −22.5 to −6.0)mainly sedentary activity
Week with running-related painno significant association with MVPA—
Not in the abstract: how many runners had an injured week, how many injured weeks there were, the device, and whether any runner cross-trained.

Mechanisms

Measured: less MVPA and more sedentary time in weeks with a running-related injury; no association with pain level.
Authors' interpretation: running-related injuries are a barrier to staying active; injury and pain behave differently and should not be conflated.
Inference: runners keep running through pain until it forces them to cut sessions, and then stop rather than switch; a commercial monitor may also under-count some substitutes (cycling, swimming) as MVPA, which would exaggerate the drop.

Practical Application

When injury stops my running, do I just end up moving less? In 49 recreational runners followed for a year, injured weeks had 14 fewer minutes a day of moderate-to-vigorous activity, mostly replaced by sitting. Observational, abstract.
Offer the substitute without being asked: the base's rule to propose a pain-free alternative (SYNTH-94) now rests on a measured gap; the choice of substitute and its dose come from REF-1428, REF-922 and SYNTH-73. Not from this paper; the base's own practice.
Pain is not the same as injury here: pain alone did not cut activity; this is no evidence that running through pain is safe (SYNTH-94 red flags and the pain-monitoring rule in SYNTH-73).
What it does not show: fitness loss, whether substitutes keep fitness in the injured (the line in SYNTH-94 that the base holds no fitness study in injured runners still holds), or competitive runners' behaviour.

Limitations

Abstract only; device, age range, sex split and number of injured weeks not given.
Observational; weeks with injury may differ in other ways (travel, illness, work).
Consumer activity monitor; MVPA from other modes may be measured less well than walking or running.
Self-defined injury (three sessions cut), not a diagnosis.
Small cohort (n = 49) of recreational runners.
Funding: "Research Support, Non-U.S. Gov't" per PubMed; no conflict statement in the record.
How this entry was checked and changed
Why this level

(from the abstract) — a small cohort (the rubric's B); MVPA comes from a consumer device and injury is defined by the runner's own changes to training