Fitness instructors read books and learn how to lead people to exercise and bring health. Teenagers. Old people. High blood pressure. How to exercise safely and effectively for different groups such as diabetic lumbar disc herniation? Can play a positive role model for members. Urge members to exercise, etc.

Bodybuilding is a sport, and bodybuilders are professionals. English is fitness, which is a very extreme thing. As far as occupation is concerned, any exercise is harmful to health. It's not just about building muscles. And symmetry. Have lines. It's not as simple as I thought to coordinate the proportion of muscles in the whole body. Exercise twice a day. Eat six to eight meals. All kinds of supplements. Have a good sleep. Strong self-discipline, no less than any other athlete. It takes ten years to succeed. It costs a lot of money.

The fitness instructor has no time. I have no money. It's not impossible to practice bodybuilding. It's basically difficult. You won't get good grades if you practice. Fitness instructors have to stand in the gym for 8 to 10 hours a day. Go every day. It's not easy to keep big muscles.