Batterystored electrical energy

Motors and jointselectricity becomes leg motion

Footfallsmotion carries the robot forward

On descents, joint motion could drive the motors as generators and return some energy toward the battery ←

Repeated leg acceleration

Lighter legs reduced the mass swung forward and back on every stride.

Electrical resistance

Integrated, lower-resistance drivers reduced energy dissipated as heat.

Foot collision

Lower contact speed softened the small impact when each foot met the road.

Slipping and descent

Gait training and regeneration limited wasted motion and recovered part of downhill energy.

42.195 kmofficial distance

4:19:52finish time

30.3 Wh/kmcalculated average

≈296 Wcalculated average draw

Calculations use the paper’s approximately 1,280 Wh race figure. They describe the whole run, not the savings attributable to any single design change.