Fig. 3From: Reducing the metabolic energy of walking and running using an unpowered hip exoskeletonExperimental setup and metabolic reductions. A Experimental setup. While a participant was walking/running with the hip unpowered exoskeleton, the spring acted in front of the hip joint to provide hip flexion torque passively. The passive force of spring (load cell), lower limb segment motion (Vicon motion capture system), muscle activities (electromyography system) and metabolic rate (indirect calorimetry) were measured. B–D Experimental protocol of the three experiments. Each experiment was performed on a separated day to prevent fatigue. The number on the figure indicates time duration of each trial. The NE condition of C refers to walking/running without exoskeleton at different speedsBack to article page