More than 16 million people each year saunter down to the golden diamond amongst the green to play the game of baseball or softball. They grab their leather mitts, they grip the seamed laces and in one fluid motion the ball is launched to their intended target. They throw the ball – a task that appears to be harmless, however, statistics may dictate otherwise.
Throwing-related injuries are becoming an epidemic in youth baseball and softball. In fact, there has been a five-fold increase in the number of serious elbow and shoulder injuries since the year 2000. Upper extremity injuries account for more than half of all injuries occurring across all competition levels, with shoulder and elbow-related injuries comprising upwards of 35% and 58% of injuries, respectively.
When analyzing the rates of the injuries according to ‘season occurrence’, the majority took place in the first half of the season. The highest rate of injury was observed in the first month of the regular season and the lowest rate was in the last month. Furthermore, a significant decrease in the incidence of injury was noted as the season progressed.
Fatigue Related Risk Factors:
According to a recent published review, one of the biggest risk factors of injury in softball or baseball is performing an overhand throwing motion to the point of fatigue. This fatigue point often occurs when individuals, specifically pitchers, throw too many pitches in one game, one season or year-round without adequate rest. Research indicates that if a youth baseball player pitches to this tipping point, then there is a 36 to 1-fold increase that he or she will injure their throwing arm.
To help prevent “throwing to fatigue” and lower the incidence of injury in the shoulder and elbow, national and international governing organizations developed criteria around the number of pitches thrown by a player in a game and the required days of rest between games. These two factors determine a player’s eligibility to play in a game.
But alarmingly, even with these regulations, a recent survey of 754 youth pitchers revealed that a significant portion engage in ‘non-recommended activities’. In fact, more than 43% pitched on consecutive days, 31% pitched on multiple teams with overlapping seasons, and 19% pitched multiple games per day. Aptly, the results of this survey also demonstrated this “lack of listening” was associated with a significant increase in subsequent shoulder or elbow injury!
Even with substantial evidence suggesting that ‘overhand overload’ contributes to shoulder or elbow injury, it is not the only risk factor that impacts the development of upper extremity injury in baseball and softball players. Instead, there are “intrinsic” factors within each individual player that may put them at risk for the development of injury.
Intrinsic Risk Factors
Deficits in range of motion, or “how much” movement is present in the throwing shoulder, may lead to shoulder injuries. When researchers analyzed Major League Baseball (MLB) pitchers with a reduction in specific ranges of motion, they found that pitchers with a significant degree of loss were over 2 times more likely to suffer a shoulder injury than those without!
If there is adequate shoulder mobility, is one exempt from injuries? Range of motion is not the only intrinsic risk factor involved in the development of shoulder injury. Muscle strength plays a critical role as well! The primary role of the “external rotators” of the shoulder, the muscles that rotate the arm outwards, is to disperse the energy created by the contraction of the opposite “internal rotators” during late cocking and acceleration phases of the throwing motion. As the “internal” and “external” rotator muscle groups perform a repeated “tug of war” whilst throwing, micro tissue tearing in these muscles can contribute to shoulder injury and weakness. Researchers have analyzed the predictive value of preseason shoulder strength to help identify players at risk for in season throwing-related injuries. It was noted that players who had specific strength reductions, had over a 30-40% chance of experiencing injury while in season!
Though shoulder strength plays a critical role in protecting against injury, there is more to the story! Lumbopelvic control is an important component to successful pitching. The lumbopelvic region includes the core muscles crossing the low back and abdomen, as well as the muscles crossing the hip joints. When analyzed, players with the poorest lumbopelvic control were three times more likely to miss greater than 30 days of the season due to injury, compared to the players with ‘good’ lumbopelvic control. A lack of lumbopelvic control may lead to an inability to efficiently transfer energy required from the legs to arms when throwing. This “road block” in the lumbopelvic region may lead to excessive use of the shoulder, arm and wrist muscles to generate enough force to achieve desired ball velocity. With inadequate core strength, muscles and ligaments in other areas of the body must compensate and over time, injuries may occur.
It has also been speculated that poor lumbopelvic control could lead to early “opening up” of the torso towards the target. This would force the torso, shoulder, and elbow to the extremes of their total ranges of movement. A “whip-like motion” occurs causing excessive joint moments that strain the ligaments and other soft tissues leading to overuse injuries.
More than 16 million people each year will engage in the game of baseball or softball. Whether one finds themselves participating in a pick-up game or a competitive championship, injuries do occur. In order to reduce risk and prevent injury occurrence, consider a consultation with your local physiotherapist.