REF-1383 · Warden et al., 2021 · Journal of Orthopaedic & Sports Physical Therapy · Paper · PubMed

Can I keep running if my stress fracture only hurts a bit?

No, by the leading bone group's practice: for a low-risk shin or metatarsal one the right load causes no symptoms during, after or the next day. Expert reasoning, untested.

Main caveat: Read from the abstract only. The paper's reasoning, the studies it draws on, its walk-run or progression details and any figures could not be checked.
thin evidenceMeasured on a mixed group

Warden, Edwards and Willy note that low-risk bone stress injuries of the tibial and metatarsal shafts account for more than half of bone stress injuries in runners, interrupt training and are managed without surgery, with the aim of a speedy but safe return. Their clinical question is what load to use.

Their answer is that the optimal load can be guided by knowledge of how a bone stress injury heals and is driven by symptoms: at all stages it "does not produce symptoms during, after, or the day following loading".

In practice they describe an initial period of load reduction, by partial or non-weight bearing, to settle the presenting symptoms; analgesics or non-steroidal anti-inflammatory drugs in the short term (sooner than 7 days) and only for resting and night pain; healing supplements such as low-intensity pulsed ultrasound or recombinant parathyroid hormone as options that "may be attempted"; cross-training to keep cardiopulmonary fitness while musculoskeletal fitness is addressed; a return-to-run programme started once the athlete has been pain free during daily activities for 5 consecutive days; progress directed by symptom provocation, first increasing running volume and only then speed; and continued optimal loading after the return, possibly with jump training or gait retraining to lower the risk of a further injury.

They call the approach clinically successful but say it requires further scientific validation.

Our reading: this is the base's second bone-specific pain rule after REF-3498 (pain-free during and after, a scoping review of tibial injuries), the first to add the next day and the metatarsal, and it is stricter than the tendon rule the base uses — no symptoms during, after or the next day, against SYNTH-36's "≤3/10, settling by the next morning".

Both are practice; this one is the practice of the group that wrote the base's bone-workload review (REF-622).

Protocol

Design: clinical commentary (background, clinical question, key results, clinical application); no search strategy, included studies or grading of recommendations in the abstract.
Population addressed: runners with low-risk bone stress injuries of the tibial and metatarsal diaphyses (shafts). n = not applicable (no participants; a commentary).
Basis claimed: the bone stress injury healing process ("the science behind the clinical reasoning").
Funding and interests: not available from the abstract or the PubMed record; Crossref lists no funder. No device maker, federation or data platform is named in what was read.

Key Results

Stage (abstract)What the authors recommendEvidence status
Every stagethe optimal load does not produce symptoms during, after, or the day following loadingauthors' clinical reasoning; untested
Starta period of initial load reduction (partial or non-weight bearing) to alleviate presenting symptoms"typically needed" (authors)
Pain medicationanalgesics or NSAIDs only short term (sooner than 7 days) and only for resting pain and night painauthors' recommendation
Healing supplementslow-intensity pulsed ultrasound and/or recombinant parathyroid hormone therapy "may be attempted"authors' option, no effect size given
While not runningcross-training to maintain cardiopulmonary fitness, while addressing musculoskeletal fitnessauthors' recommendation
Restart runningonce pain free during daily activities for 5 consecutive daysauthors' threshold; untested
Progressiondirected by symptom provocation; running volume before speedauthors' recommendation
After the returncontinue optimal loading; may include jump training and/or gait retraining to reduce subsequent BSI riskauthors' option
Overall"clinically successful, but requires further scientific validation"authors' own statement
Not in the abstract: any study data, return times, walk-run schedules, mileage steps, the definition of "symptoms", or a grading of the recommendations.

Mechanisms

Measured: nothing in the abstract; the paper argues from the healing process of bone stress injuries.
Authors' interpretation: knowledge of how a bone stress injury heals can guide the load, and symptoms are the practical gauge of whether a load is within what the healing bone tolerates; low-risk shaft injuries can therefore be managed non-invasively with symptom-guided loading.
Inference: the rule differs from the base's tendon rule for a reason that fits the biology the base already holds: a bone stress injury is repeated loading outpacing repair (PHYS-37), so pain during loading signals damage accumulating faster than repair, whereas in tendinopathy some pain during loading was tolerated in the one trial the base holds (REF-628, pain up to 5/10 in that trial's model).That is our reading of why "symptom-free" is the bone rule; the abstract states the rule, not this reasoning.

Practical Application

Can I keep running if my stress fracture only hurts a bit? No, by the leading bone group's practice: for a low-risk shin or metatarsal one the right load causes no symptoms during, after or the next day. Expert reasoning, untested.
The bone pain rule is symptom-free, not ≤3/10: at every stage of the return the load should produce no symptoms during the session, after it, or the following day (C+, clinical commentary, from the abstract).This replaces, for bone, the tendon ceiling that SYNTH-36 gives in the same bullet as its tibial return ("≤3/10, settling by the next morning"), which is the base's practice borrowed from the Achilles trial model (REF-628). REF-3498 (C+, full text in the base) points the same way: pain during activity indicates overload, and the return should be pain-free during and after.
When to start running again: after a period of load reduction, once daily activities have been pain free for 5 consecutive days; then running volume first, speed later, each step gated by symptoms (the authors' threshold and order; untested). The clinician who made the diagnosis owns the start; walk-run steps are in REF-3498.
Painkillers are not a way to keep training: the authors allow analgesics or NSAIDs only in the short term (sooner than 7 days) and only for pain at rest or at night, which agrees with SYNTH-73's "Never mask pain to train" (practice).
Keep the engine running: cross-training maintains cardiopulmonary fitness while the bone heals (the authors' recommendation; which modality and how much are not in the abstract). Not from this paper; the base's own practice: a pain-free substitute with some intensity kept (SYNTH-73 substitution lines, healthy-runner data).
What it is good for as a source: the bone-specific load rule (symptom-free during, after and the next day), the start trigger (5 consecutive pain-free days of daily activity), volume before speed, and the narrow role of painkillers, as the practice of the group that leads the field. What it does not show: that this approach is better than any other or how long it takes; anything for high-risk injuries, including the sites REF-1379 found most complication-prone (femoral neck, tarsal navicular, anterior tibial shaft, fifth metatarsal); any tested threshold; how much cross-training keeps fitness; whether the healing supplements work.

Limitations

Read from the abstract only. The paper's reasoning, the studies it draws on, its walk-run or progression details and any figures could not be checked; nothing beyond the abstract is claimed here.
Practice, not evidence. The authors state that the approach "requires further scientific validation"; no trial compared a symptom-free rule with a pain-tolerant one for bone, and the 5-day and 7-day figures are the authors' practice.
Scope. Low-risk tibial and metatarsal shaft injuries in runners only; high-risk sites, other bones and non-runners are outside it.
Healing supplements. Low-intensity pulsed ultrasound and parathyroid hormone are named as options that "may be attempted"; the abstract gives no evidence for them, and they are medical decisions.
Funding and interests: not available from the abstract or the PubMed record; Crossref lists no funder. No device maker, federation or data platform is named.
How this entry was checked and changed
Why this level

(from the abstract) — a narrative clinical commentary whose load prescription is the authors' clinical reasoning from bone-healing biology; the authors themselves say it "requires further scientific validation", and no study in the abstract compares it with another return approach. The same group's narrative review in the base is graded C+ (REF-622); the rubric's B+ for leading-group narrative reviews is not used because what this entry carries is an untested protocol, not a summary of measured evidence. Read from the abstract (closed access; Europe PMC holds no full text; the one repository copy OpenAlex lists answered with a bot-check page and was not used)