The jitter frequency is high, and the exerciser can't keep up. Felix Rod is a fitness tool to exercise muscles and has a high reputation. Its main function is to train muscles daily and improve body perception. Users who generally use Felix Rod can't hold on to 10 second. The main reason is that this kind of fitness tool has a high shaking frequency, and the bodybuilders can't keep up. You just need to feel the shaking amplitude to solve this problem.