When you practice alignment for standing postures, dingshi or zhanzhuang, you should be very relaxed. Don’t use strength, but instead to stabilize your frame or posture, you need to work with opposite forces as well as complementary forces.
Shown here, expansion is made by expanding the frame as a whole, like blowing up a balloon. But for contraction, lines of force are created. The hands press against each other, towards the shoulder or the centerline.
Complementary forces in other directions are used to move the frame, change the frame or to connect the upper body with the legs and feet.
When you are working with free tuishou or with applications practice, you should always find some other way than to force the movements. The answer to get an application right or get out of a sticky situation is ususally the same: Not by using force, but by a clever and dynamic use of structure.