Identifying which pitchers are at risk for injury in minor and major league baseball
Importance of understanding pitchers' level of injury risk
Injuries to athletes in professional sports are detrimental across the board, affecting not only the athlete, but the entire organization and all who are connected to it, making injury risk assessment an incredibly imperative task. When it comes to baseball pitchers, who play a major part in the outcome of each game, the level of this risk evaluation becomes even more important. The repetitive, demanding nature of the overhead motion in pitching causes massive amounts of energy transfer from the lower to upper extremities, which puts excessive stress on certain areas of the body. There are also dynamics of a pitching throw, such as compressive forces put on the glenohumeral joint and elbow varus torque, that have been identified as possible sources of overuse injury to the shoulder and elbow, making pitchers more prone to injury than other players. Weakness of shoulder external rotators when compared to internal rotators is also believed to lead to injury, but is yet to be confirmed. With the ultimate purpose of helping baseball organizations make better educated decisions on their potential pitchers, a study was conducted that sought to analyze the predictive value of preseason shoulder strength measurements in identifying players at risk for in-season throwing related injury.
Detailed assessment of both major and minor league pitchers taken
Data was taken over a five-year period, during which 144 major and minor league pitchers participated in the preseason strength training protocol, and were subsequently followed throughout their seasons for incidences of injury. The only inclusion criteria was participating in preseason workouts as an active pitcher on the roster and having no restrictions on throwing activity. A certified athletic trainer took strength assessments in an isometric manner according to specific protocol, with measurements taken in the throwing arm for prone internal rotation (IR), prone external rotation (PER), seated external rotation (SER) and supraspinatus (SS). After preseason, pitchers were monitored during the season for any throwing-related injury and each was categorized as no injury (0), injury not requiring surgery (1), or injury requiring surgery (2). An injury was defined as any condition resulting in the athlete's placement onto the disabled list and/or missing at least one game due to the condition.
Strong connections shown between strength and likeliness of injury
Over the five-year period, there were a total of 70 injuries in 50 players, with 42 shoulder injuries and 28 elbow injuries, of which, coincidentally, 42 were treated non-operatively and 28 surgically. When data from preseason assessments was applied to these findings, strong evidence was found of an association between PER strength, SER strength and SS strength with throwing-related injuries requiring surgical intervention. There was also evidence of an association between the ratio of PER/IR and the likelihood of any throwing-related injury. Other significant associations were found between PER strength and SS strength with shoulder injury requiring surgery, as well as between SS strength and the ratio of PER/IR with the likelihood of any shoulder injury. Additional analysis also showed that the ratio of external to internal rotator strength was associated with any type of shoulder injury and there was a trend of that imbalance leading towards an overall incidence of injury.
These findings clearly show that certain muscle weaknesses can lead to injury. A tendency pointing to the importance of external rotator strength appears to emerge as well. Taking that into consideration, pitchers should be assessed in these specific areas annually during preseason, and measures should be taken in attempts to prevent injury. From there, preseason and intra-season strength training should focus on the posterior rotator cuff and supraspinatus, particularly in players who are weaker in those areas to begin with.
-Summarized by Greg Gargiulo
-As reported in the May 20, '10 edition of The American Journal of Sports Medicine
