Because force is generated with help from the ground, bending your knees places your body in better position to produce trunk, hip, and shoulderrotation.
因为力量源自地面,弯曲你的膝盖能让你的身体处于一个更易通过躯干,髋和肩部转动获得能量的绝佳位置。
2
The arm and shoulderrotation stretch warms up the muscle that surrounds the shoulder jointed the body. These muscles are used continuously during swimming.