Background Exercise-based interventions have consistently been associated with a reduction in injury rates in sports such as football. Although the injury burden in rugby union (‘rugby’) is high, such interventions have not been evaluated in rugby.

Objective To evaluate the effectiveness of the BokSmart Safe Six on (i) the injury risk profile and burden in junior rugby players in South Africa, and (ii) the injury prevention behavioural determinants of the coaches of these players.

Design A pragmatic cluster-randomised controlled trial, with no blinding of groups.

Setting Male youth rugby players from two geographically-separated locations in South Africa over the 2017 rugby playing season.

Patients (or Participants) Youth rugby players (14–16 year old) (n=160 players in the intervention group; n=160 in the control group) will be recruited from the Western Cape Schools Premier Division. This sample size provides sufficient power to detect meaningful differences.

Interventions (or Assessment of Risk Factors) The teams will be randomly allocated to groups that either: (i) have the BokSmart Safe Six coach-delivered exercise intervention in their warm-up (experimental group), or (ii) continue with their usual warm-up (control group). Injury risk profiles will be assessed on all players through musculoskeletal screening performed at the beginning, middle and end of the trial. Epidemiological measurements include injury surveillance at all matches and training sessions, and exposure to the various warm-up exercises (including BokSmart Safe Six exercises). Behavioural determinants of coaches will be assessed before and after the intervention through standardised theory of planned behaviour questionnaires and focus groups.

Main Outcome Measurements Comparison in injury risk profiles and burden of injury between the intervention and control groups. Changes in the behavioural determinants of coaches.