Rationale for not pushing from leg

Rationale for not pushing from leg

So much Tai Chi is done by pushing the body forward and backward using the leg strength. The energy from any push ends at the junction of the joint and surrounding tissue. In this case, it ends at the hip joint which is the largest joint in the body. This has the same effect, sometimes deleterious effect as a hard snapping punch has on the shoulder, and other joints in the arm.
via YouTube https://www.youtube.com/watch?v=ELASrmijpuc