Some thoughts. The steps do not end with dropped leg. They one step end is the starting point of the next one. Every step step keep at least a little stretching, this will help in the structure and the movement. So this force is very important.
See one example.
When step forward and backward, best using / having the bridge 襠 ( dāng )
Check more details at the 【推敲太極拳】【20200104(xx)】 at the Taichi 2020 channel.