Friday, January 19, 2018 Study: To Avoid LBP, Runners Should Think Deep Even though they are keeping fit, up to 14% of American runners experience low back pain (LBP) each year. But runners can reduce their risk by developing their deep core muscles, say authors of a recent study in the Journal of Biomechanics (abstract only available for free). While many fitness enthusiasts focus on their abs, they may neglect the trunk muscles they can’t see. “Improper function of this musculature may lead to abnormal spinal loading, muscle strain, or injury to spinal structures, all of which have been associated with increased low back pain risk,” say researchers. To test this idea, authors used motion capture technology to collect kinematic data from 8 participants with no history of back pain and no recent injuries. The data, gathered while the participants ran, was used to create simulated full-body models in OpenSim, a software tool for modeling movement. In the simulations, researchers gradually weakened the models’ deep core muscles, both individually and together. They found that when deep core muscles are weak, superficial core muscles, particularly the superficial longissimus thoracis (LT), tend to overcompensate, which may result in muscle injury or fatigue. And since the superficial LT was most often the muscle overcompensating for weak deep core muscles, it may be “most at risk for fatigue or injury” if deep core muscles are not functioning properly. The authors believe that certain deep core muscles appear to be more important than others in runners. “The deep erector spinae required the largest compensations when weakened individually,” note authors, who conclude that “it may contribute most to controlling running kinematics.” When all deep core muscles were weak, or when only the deep erector spinae was weakened, there was a significant increase in both compressive and shear spinal loading in the upper back, with a decrease in the lower back. Over time, this could result in damage to the spine and increase the risk of injury, authors warn. Authors suggest further research using simulated models to examine core function in running. The study, researchers observe, “is the first step in providing evidence to support the common notion that poor core strength and stability may influence a runner’s risk of developing injuries such as LBP.” Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.