Background Participants of team ball sports will commonly experience more than one injury over a period of participation. Recording/reporting this can be difficult but it is necessary to provide the most accurate estimates of sports injury incidence.

Objective To identify the current methods used to report more than one individual injury in studies of injury incidence in team ball sports.

Design Systematic review of literature.

Setting Studies of injury incidence in team ball sports.

Patients (or Participants) Studies were included if they: reported incidence of all injuries (not specific to one injury type) over the whole time period (e.g. not game-injuries only); were conducted with participants of team ball sports; collected data prospectively; had a follow-up time of >1 calendar-year or ≥2 consecutive-seasons; collected data in a defined cohort (e.g. club, school); used an individual identifier in the collection of data.

Interventions (or Assessment of Risk Factors) None.

Main Outcome Measurements Number of included studies, definitions of injury and summary of how multiple individual injuries were reported.

Results There were 71 studies included, from which the most common presentation of data was pooled injury counts summarised across teams/seasons (n=34). Where multiple injuries were reported (n=37), most studies (n=20) were limited to recurrent injuries only (exact same body part and type.) Eleven studies presented the mean number of injuries per athlete for a specified time (season, study-duration), eight studies reported the range of injuries in athletes. Used infrequently was a measure of risk of injury in subsequent seasons or a statement that some athletes had >1 injury in the season.

Conclusions Injury prevention relies on accurate incidence estimates. Ongoing development of methodology in this area is encouraged to advance understanding of the causal underpinnings of sports injuries, and their prevention.