Rue 2004.

Methods	Randomised, placebo‐controlled trial
Participants	Setting: US Naval Academy Size: 40 midshipmen with 58 stress fractures; data reported for 26 (14 in the treatment group and 12 in the control group) midshipmen with tibial stress fractures. Baseline characteristics: 23 men and 17 women; mean age 19 years; fractures sites were tibia, metatarsal, femur and fibula (74%, 9%, 5% and 5% respectively) Inclusion: new midshipmen sustaining stress fractures diagnosed on radiographic and scintigraphic examinations during initial training. Informed consent. Exclusion: none
Interventions	While not stated explicitly it is likely that all participants received the standard‐of‐care treatment that included protected weight bearing if normal walking reproduced symptoms, alternative aerobic exercise, a daily multivitamin and calcium supplementation (twice daily 500 mg). Test: daily 20‐minute LIPUS treatment (Exogen Inc, Piscataway, NJ) administered by sports medicine personnel until stress fracture had healed. Control: similar protocol with a sham unit.
Outcomes	Follow‐up schedule: daily treatments until fit to return to duty (work) defined as no pain on palpation, the ability to do a single leg hop on the affected side without pain and radiographic evidence of healing. Primary outcome: time to return to duty (work). Secondary outcome: adherence.
Notes	Although 40 participants were enrolled with a variety of injured bones, only 33 were able to comply with the protocol for a variety of reasons. Of these 33, 7 further participants were excluded from the analysis as only those with fractures of the tibia were analysed (total attrition: 14 of 40). The 26 participants had 43 tibial stress fractures ‐ time to return to duty was based on stress fracture site with the longest duration of symptoms.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...and were randomized into one of two treatment protocols..." Comment: No description of sequence generation.
Allocation concealment (selection bias)	Unclear risk	Quote: "...and were randomized into one of two treatment protocols..." Comment: No description of allocation concealment.
Blinding (performance bias and detection bias) Patient‐reported measures	Low risk	Quote: "The placebo group underwent the identical protocol, except that the stimulator unit was non‐functional. This study was a double‐blind, placebo‐controlled investigation." Comment: Participants were blinded to intervention.
Blinding (performance bias and detection bias) Objective measures	Unclear risk	Quote: "This study was a double‐blind ... investigation." Comment: Trial personnel administered the treatments and documented adherence. It is not explicit that they were also blind to the allocation although the study was 'double‐blind'.
Incomplete outcome data (attrition bias) Patient‐reported measures	High risk	Overall attrition proportion was 14 of 40 and the loss was explicitly systematic.
Incomplete outcome data (attrition bias) Objective measures	High risk	Overall attrition proportion was 14 of 40 and the loss was explicitly systematic.
Selective reporting (reporting bias)	Unclear risk	No protocol available.
Other bias	Low risk	No additional biases identified
Selection bias (imbalance in baseline characteristics)	Unclear risk	Smoking status is not reported.