Not necessarily, but it would be better to have muscles. The training time of personal trainer is about 3 months. Training institutions can make a comprehensive choice according to the teaching mode, teaching environment and teaching staff of fitness instructor training professional institutions. If you want to be a fitness instructor, you can get a national fitness instructor certificate. At present, the national professional certification of fitness coaches is a necessary professional certificate for fitness coaches in China, which is more formal, authoritative and legally effective. We can take the national fitness instructor certificate, and fitness instructors need to learn fitness skills and professional knowledge.