Hello, 16 years old can start preliminary fitness training. But the training should not be too heavy, and the weight can be increased step by step. Don't worry about affecting your height. Proper fitness training will not affect your growth. Ossification is still going on at normal speed. Most professional bodybuilders in the United States are above 180cm in height, and of course there are genetic problems. Now you can do more exercises such as stretching your limbs, jumping and using your own weight. Single muscle training will make the body develop non-parallel. You can also do more exercise. The combination of aerobic exercise and non-itchy exercise can maximize the development of one's physical fitness. thank you ...