485 MEP030 – Hamstring injury patterns in professional baseball: a systematic video analysis of 47 injuries

AbstractBackground Hamstring strain injury (HSI) is the most common injury in Major League Baseball (MLB), frequently leading to prolonged symptoms, sub-optimal healing, and high re-injury rates.Objective To describe the situational patterns of HSI in professional baseball.Design Retrospective systematic video analysis.Setting Professional baseball; MLB.Participants Professional baseball athletes participating in the 2021 regular MLB season (April 1 2021 to October 3 2021).Results Of the one hundred and ten HSIs that occurred during the regular season (1 injury per 44 games), 47 (43%) were clearly identified on video footage and included in the video analysis. More than two-thirds of the injuries (68%) occurred in the first half of the season. Thirty-two injuries (68%) were sprint-related while 15 (32%) were stretch-related injuries. Of the sprint-related injuries, 29 (91%) involved a baserunner running to a base, with 18 of these injuries happening in the 20–30yd range (62%), 4 in the 30–40yd range (14%), 4 in the >40yd range (14%), and 3 in the <20yd range (10%). Twenty of the baserunning injuries (69%) occurred within 3 steps before or after stepping on a base. Of all baserunning HSI involving the starting lineup, 11 (39%) occurred in the first two innings. More than half of all baserunning injuries (52%) injuries occurred in the first 2 months of the season. Of the 15 stretch-related injuries, the most common injury situation was when a pitcher extended their front knee in hip flexion during follow-through (53%). The other stretch-related injuries involved fielders stretching to field a ball (20%), baserunners stretching to step on a base (13.5%), and baserunners sliding feet-first (13.5%).Conclusions HSIs in professional baseball occur through running- and stretch-related mechanisms. Most running-related injuries happened during baserunning and occurred in the 20–30yd range. Most stretch-related injuries occurred in pitchers during their follow-through.