Baseball’s approach to preventing arm injuries so far has been to try to limit loads on the arm itself. But more and more evidence seems to suggest some of the prevention efforts should be focused further down the kinetic chain.
The incidence of Tommy John (ulnar collateral ligament [UCL]) surgery continues to increase at an alarming rate, and in increasingly younger players. Pitch counts and innings progressions just don’t seem to be working.
Many experts are starting to explore the idea of early sports specialization as a contributor. We know that highly specialized youth athletes are those most likely to have a serious injury (see “Specialization, weekly training loads contribute to risk in youth athletes”). In baseball, where per-game pitch counts have little effect given that many kids play on multiple teams concurrently, it’s easy to see how specialization can lead to excessive upper extremity loads.
But that’s only half of the specialization equation. Not only are aggressive coaches and parents overloading young players’ upper extremities, they’re doing so at an age when the children’s lower bodies are particularly ill-equipped to support that extra load.
That’s the take-home message from a study performed at the Kerlan-Jobe Orthopaedic Clinic in Los Angeles and epublished in early August by the American Journal of Sports Medicine. The authors assessed scapular and hip mechanics in 108 baseball players aged between 7 and 18 years and compared preadolescents (aged 7-12 years) with adolescents (aged 13-18 years).
The 54 preadolescents in the study competed for 5.7 months of the year on average, while the 54 adolescents competed for 9.2 months. That alone probably makes it unsurprising that the incidence of scapular dyskinesis on the throwing side in the older players was double the incidence in their younger counterparts (50% vs 25.9%).
But what’s really interesting is that, when the kids were asked to perform a single-leg squat to assess core and gluteal strength, even after given time to practice, hardly any of them could do it correctly. None of the preadolescents performed the test without errors, and the adolescents didn’t do much better, with success rates of just 13% on the stance leg and 9.3% on the stride leg.
The authors suggest the poor performance indicates that young players lack the proprioceptive ability or the core or gluteal strength (or all of those) required to provide a solid foundation for the upper extremity during month after month of competition. And, they suggest, this weak link in the kinetic chain may predispose young players to shoulder and elbow injuries.
Adding heft to this idea is a 2013 Journal of Orthopaedic and Sports Physical Therapy study in which scores on the Y-Balance Test-Lower Quadrant (which assesses lower extremity strength, range of motion, and neuromuscular control) were significantly lower in high school and college baseball players with UCL tears than in uninjured players.
More study is clearly needed. And core and lower extremity training in young baseball players by itself probably will not save immature arms from the effects of overuse. But, if implemented in conjunction with the existing preventive measures and a little common sense, it could give them more of a fighting chance.