Background Shoulder injuries are common in swimmers. However, prevalence and risk factors for shoulder injuries in talented, competitive swimmers are unknown.

Objective To gain insight in the prevalence and risk factors for shoulder injuries in talented swimmers.

Design A prospective cohort study was conducted.

Setting Talented, Dutch swimmers, competing at National or International level, swimming at talent or training Centres of the Royal Dutch Swimming Federation.

Patients (or Participants) 128 swimmers were included at the start of the study. Five swimmers were excluded due to missing technique data, five swimmers quit their swimming career during the follow-up for different reasons than shoulder injuries. Data of the remaining 118 swimmers were included into the analyses.

Interventions (or Assessment of Risk Factors) At baseline the following swimming technique was recorded during a 200 m race: 1. Maximal forward flexion in the shoulder joint during glide phase; 2. Crossing the vertical midline axis of the swimmers body with the hand during thrust-phase; 3. Dropped elbow (elbow at a lower level than line shoulder-wrist), at hand entry or early pull-through. Furthermore, online questionnaires were send to the participants on a two-weekly basis to record the time-loss shoulder injuries.

Main Outcome Measurements A time-loss shoulder injury was defined as: ‘a shoulder complaint occurred as a result of participation in swimming practice or competition, resulted in the restriction of swimmers participation of at least 1 day’. Prevalence and incidence rates were calculated.

Results In total, 28,8% of the swimmers sustained a shoulder injury during 1 year. Chi-squared tests showed an association between crossing the midline during thrust-phase and shoulder injuries (p-value=0.03). No significant association was found between the two other swimming techniques and shoulder injuries.

Conclusions The prevalence of shoulder injuries is high in talented, competitive swimmers. Crossing the midline during thrust-phase may be a risk factor in developing shoulder pain.