The effect of manipulating vertical motion on running economy

While several biomechanical factors have been identified as key determinants of running economy (i.e. metabolic cost), the influence of individual mechanical factors such as center of mass vertical motion (ΔCoMz) remains unclear. The purpose of this study was to determine how manipulating ΔCoMz effects running economy. Twelve runners used a visual biofeedback system to control their ΔCoMz during running as we measured the metabolic, kinematic, and muscle activation responses to the different levels of ΔCoMz. Running economy was strongly correlated to ΔCoMz and was optimized at an intermediate center of mass vertical motion of 6-8cm. Changes in ΔCoMz 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