The elbow muscle strength of baseball pitchers could play a bigger role in injury risk and prevention than previously thought, according to biomedical researchers at Northwestern University.
Their study, recently published in Annals of Biomedical Engineering, used a novel computer model similar to that used to study upper limb control in prosthetic devices. The researchers reproduced pitching motion recorded from a high school player to explore how individual muscles affect ulnar collateral ligament loading (UCL), and how changes in muscle output can either relieve or exacerbate that load.
“Our simulations illustrate that if the muscles were doing nothing, then the bones that make up the elbow joint could have been pulled apart during that single pitch,” Wendy M. Murray, associate professor of biomedical mitering at Northwestern’s McCormick School of Engineering and Applied Science and co-author of the study, stated in a press release. “In contrast, we also were able to implement reasonable assumptions about muscle performance that showed how the very same pitch could result in no load on the UCL at all.”
Findings also showed that the medial elbow muscles generated substantial, protective varus elbow moments during simulation. The triceps generated large varus moments at the time of peak valgus loading. Varus moments generated by the flexor digitorum superficialis were larger, but occurred later in the motion, the researchers found.
Additionally, increasing muscle-tendon force output, either by augmenting strength parameters or activation levels, decreased the load on the UCL. Researchers stated the data could enable targeted training of specific muscles and more accurate assessments of UCL vulnerability, potentially reducing the number of elbow injuries in the future.
Buffi JH, et al. Ann Biomed Eng. 2015;doi:10.1007/s10439-014-1144-z.