drag surface meaning in English
叶背
Examples
- An elevation of the shoulder , medial rotation of the upper arm , and late flexion at the elbow as the body rotates to accommodate an " elbows - up " position and to reposition the forearm / hand drag surface to where forward propulsion can be created
提肩，上臂转一半，然后屈肘使身体转动达到一个高肘位置接着重新入水并使前臂和手掌通过抱水能够产生向前的推进力。