Hamstring injuries in elite Gaelic football: an 8-year investigation to identify injury rates, time-loss patterns and players at increased risk

Background Hamstring injuries occur frequently in field sports, yet longitudinal information to guide prevention programmes is missing. Aim Investigate longitudinal hamstring injury rates and associated time loss in elite Gaelic football, while identifying subgroups of players at increased risk. Methods 38 data sets from 15 elite male Gaelic football teams were received by the National Gaelic Athletic Association (GAA) Injury Surveillance Database between 2008 and 2015. Injury and exposure data were provided by the team's medical staff via an online platform. Results 391 hamstring injuries were sustained accounting for 21% (95% CI 20.0% to 21.7%) of all injuries. Prevalence was 21% (95% CI 19.2% to 23.4%). Incidences were 2.2 (95% CI 1.9 to 2.4) per 1000 exposure hours, and 7.0 (95% CI 6.5 to 7.1) times greater in match play than in training. Typically each team sustained 9.0 (95% CI 7.0 to 11.0) hamstring injuries per season affecting the: bicep femoris belly (44%; 95% CI 39.4% to 48.7%); proximal musculotendinous junction (13%; 95% CI 9.8% to 16.3%); distal musculotendinous junction (12%; 95% CI 8.6% to 14.9%) and semimembranosis/semitendinosis belly (9%; 95% CI 6.3% to 11.7%). similar to 36% (95% CI 31.5% to 41.0%) were recurrent injuries. Mean time loss was 26.0 (95% CI 21.1 to 33.0) days, which varied with age, injury type and seasonal cycle. Hamstring injuries accounted for 31% (95% CI 25.8% to 38.2%) of injury-related time loss. Previously injured players (rate ratio (RR)=3.3), players aged 18-20 years (IRR=2.3) or >30 years (RR=2.3), as well as defensive (IRR=2.0) and midfield players (RR=1.5), were most at risk of sustaining a hamstring injury. Comparisons of 2008-2011 with 2012-2015 seasons revealed a 2-fold increase in hamstring injury incidences. Between 2008 and 2015 training incidence increased 2.3-fold and match-play incidences increased 1.3-fold. Conclusions Hamstring injuries are the most frequent injury in elite Gaelic football, with incidences increasing from 2008-2011 to 2012-2015. Tailoring risk management strategies to injury history, age and playing position may reduce the burden of hamstring injuries.