Correlation between running asymmetry, mechanical efficiency, and performance during a 10 km run.
Running asymmetry is considered a matter of concern for performance and injury, but the association between asymmetry and performance remain unclear. There are different strategies to address asymmetries and its relationship with performance. Here we investigated the correlation between global symmetry index and mechanical efficiency during 10 km running. Thirteen amateur trained athletes (8 men and 5 women) performed a 10 km running at a fixed pace while a 3D accelerometer attached to the pelvic region recorded position data throughout the course of the run and gas exchanges were monitored breath by breath. Global symmetry index was determined for 3 directions, and mechanical efficiency was calculated as the ratio of external work output to energy expenditure determined from gas analysis. Global Symmetry Index and mechanical efficiency decreased (-55.5% and -44.8%, respectively) during the course of the 10 km run (p < 0.01). A positive correlation was observed between global symmetry index and efficiency (r = 0.66, p = 0.01). Asymmetry in the vertical direction had a relatively higher impact on the global symmetry index. The global symmetry index accounted for 43.1% of the variance in mechanical efficiency (p = 0.015). Symmetry, evaluated by the global symmetry index, directly correlates with mechanical efficiency during a 10 km run.