By Dev K. Mishra, M.D.
President, Sideline Sports Doc
Clinical Assistant Professor of Orthopedic Surgery, Stanford University
- A recently published study attempts to show cause and effect for some specific attributes of young baseball players leading to arm injury
- The study identified several factors with high risk of elbow injury in young baseball players, including pitching >100 total innings per year, training and playing more than 16 hours per week, and having a history of elbow pain
It would be great if we could take a young baseball player and be able to accurately predict arm injury risk for that player. If we could identify specific factors we could take steps proactively to prevent injury. A recently published study shows that we are closer to being able to identify cause and effect for elbow injuries in young baseball players but still need quite a bit more data to conclusively show cause and effect for shoulder injuries.
Most studies on arm injuries to young baseball players tend to be surveys or retrospective reviews. With those types of study designs it’s very difficult to say that certain factors cause an injury. Instead we are able to say that the factor is “associated” with an injury. We combine the available data with decades long experience from skilled professionals and come up with consensus recommendations. Many of the recommendations around type of pitch, innings thrown per year, hours of participation per week, etc. are based on this type of reasoning. And there is very little data for other field players regarding injury risk.
To prove that a behavior causes an injury requires a different type of scientific study. We like to see forward looking or “prospective” studies with comparison groups. The published study is a systematic review of the currently available prospective studies.
These were the factors identified that showed a causal effect in youth baseball players:
- For shoulder injuries, a preseason rotation deficit (especially internal rotation) was a significant risk factor
- For elbow injuries they identified several factors:
- Pitching >100 total innings per year
- Age 9-11 (meaning that just being in this age group is a risk factor…)
- Being a pitcher or catcher
- Training and playing more than 16 hours per week
- Having a history of elbow pain
I am still a believer in the MLB Pitch Smart recommendations, even though only one of the Pitch Smart factors was identified as a factor in the referenced scientific study (pitching more than 100 total innings per year). We need more high quality studies to definitively lead to stronger recommendations, but until then I would say it’s wise to follow the MLB Pitch Smart guidelines for the younger players.