Why can't I feel my skin shaking when I use PPM4331 Massage Belt?

PPM4331 Massage Belt is a multi-speed settings, different massage strength presents different effects, such as the use of low massage strength may not appear skin shaking. The degree of skin shaking is also related to the degree of personal lumbar laxity, such as your waist and abdomen is tighter, the skin shaking feeling is weak, such as your waist and abdomen is more flaccid, the skin shaking feeling obvious.