Implications of Fatigue and Stability on Neuromuscular Control and Injury Risk in Recreational Runners

All dates for this event occur in the past.

Scott Lab E525
201 W. 19th Avenue Columbus, OH 43210
Columbus, OH 43210
United States

Name: Nelson Glover

Abstract:
Running is a critical activity in promoting the public's well-being but running-related injuries (RRI) often interrupt training regimens. Identifying the risks that determine a runner’s likelihood of injury through biomechanical factors has been important to researchers. Despite the breadth of research, there are still many unknown factors that may influence injuries in runners. A deeper understanding of suboptimal conditions and runners’ biomechanical and neuromuscular compensations may help inform intervention strategies to mitigate injuries. Fatigue is a condition that most runners experience during their regular runs that cause deficits in muscle function, but little is known about specific neuromuscular control adaptations in runners. In addition to fatigue, external perturbations commonly experienced in runs can potentially alter the biomechanics and control of runners broadly, and the injury risk of these adaptations is largely unknown. This dissertation aimed to assess the injury risk associated with fatigue and running under destabilizing conditions and characterize the changes in neuromuscular control. The biomechanical and neuromuscular control compensations resulting from a run to volitional fatigue and after experiencing acute perturbations were examined. Decreased coactivation of the quadriceps and hamstrings around the knee and ankle and reduced trunk control were observed in fatigued running. Further analysis revealed that the altered trunk control and ankle coactivation during the weight acceptance phase of stance have strong influences on increases in peak vertical instantaneous loading rates, a risk factor for RRI. Perturbations created significant changes in neuromuscular control, altering the coactivation of the knee and ankle muscles throughout the stance phase. This analysis of control was extended by examining the changes in local dynamic stability of the runners after experiencing one of the acute perturbations. A proposed change in global neuromuscular objective while fatigued was tested through implementation as a cost function in musculoskeletal optimization. Accounting for decreases in joint contact forces likely caused by reductions in knee coactivation, optimizations using a joint loading reduction objective function could better estimate muscle activity. Findings from this study suggest that significant changes in control occur when running in destabilizing conditions and running with fatigue. Adaptations to fatigue can lead to increased injury risk, influenced by changes in neuromuscular control objectives. Adaptations to acute perturbations can be neuromuscular or characterized by the stability of the running motion.

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