Biomechanics predict changes in metabolic cost during running and hopping at different frequencies

The rate of force production (1/tc; tc is ground contact time) and volume of active muscle (Vm) account for 62% of the metabolic cost of running over a wide range of step frequencies. Additionally, 1/tc and Vm account for 48% of the metabolic cost of hopping at the same range of frequencies. Thus, 1/tc and Vm provide a moderate prediction of the metabolic cost of bouncing gaits across step frequencies.