The right knee kicksdown through knee extension. The left knee begins knee flexion.
右膝通过膝盖拉伸向下踢水,左膝开始弯曲膝盖。
2
He kicks it down the hill.
他把它踢下了山。
3
The generator kicks in only during the swing phase of a footstep when the muscles are already braking, so it doesn’t take power away from your step and slow you down.