Effects of manipulating center of mass vertical motion on running economy

While several biomechanical factors have been identified as key determinants of running economy (i.e. metabolic cost) [1], the influence of individual mechanical factors such as center of mass (CoM) vertical motion remains unclear. The purpose of this study was to determine how manipulating CoM vertical motion effects running economy. Twelve runners used a visual biofeedback system to control their CoM vertical motion during running as we measured the metabolic, kinematic, and muscle activation responses to the different levels of CoM vertical motion. Running economy was strongly correlated to CoM vertical motion and was optimized at an intermediate CoM vertical motion of 6-8cm. Changes in CoM vertical motion were associated with changes in ground contact time (TC), stride length (SL), and peak knee flexion angle, as well as the magnitude of Biceps Femoris (BF), Vastus Lateralis (VL), and Tibialis Anterior (TA) muscle activation.