1. When going up the stairs, the center of gravity of the human body movesforward, and the back is automatically stretched.2. The step is automatically stretched back, so that the center of gravity of thehuman body sinks, and the whole foot supports the next step.3. Squat automatic back extension to achieve balanced squatting of both legs, andsolve the problems of poor stability and difficulty of one-foot support.4. Two-way adjustment of plantar flexion and dorsal extension provides asmooth transition of the center of gravity, and the upper and lower slopesare like walking on the ground.

5. Two-way pressure adjustable.

6. Forming a linkage effect with the knee joint.