正如多数研究所提到的拉力螺钉的一个主要优点是反向滑动机制，能在负重条件下对骨折施加控制性加压，促进骨折的愈合。

As it is mentioned in many studies that one major advantage of the backward sliding mechanism of lag screw is controlled compression of fracture with weight bearing which helps in healing of fracture.

youdao

反向屈腕：找个地方坐下，将拉力绳在双脚缠绕两圈。

Reverse Wrist Curls: In a seated position, wrap the band twice around the feet.

youdao

The rope is being pulled backwards by this guy, the T.

绳子也会被这个物体朝反向拽,拉力也是 T

耶鲁公开课 - 基础物理课程节选