On this issue, I think that "with the efforts of most people, it is impossible to gain muscle." Efforts not only refer to exercise, but also include subsequent recovery, especially a series of steps of nutritional supplement. Are you afraid of becoming a professional team? Don't worry, their training intensity is nonhuman, about 8 km- 10 km or more every day. We will eat a nutrition stove and start training at 5/6 in the morning. If you have nothing to do, you have to go to fitness equipment to practice small muscle groups. If it takes several years or even longer, after amateur swimming and normal diet, we swim two kilometers a day. What do you think is the possibility of growing muscles? Losing fat is really good. If you still don't feel at ease, well, from my personal experience, I used to swim1500m at noon every day, five times a week, for about 45 minutes to 50 minutes each time, for about a year and a half. Others ate and slept (not overeating, eating normally). My weight is about 5 kg to 6 kg, compared with the data of fat detector (muscle content and other data). As for stopping training, it is easy to say that it will definitely rebound after ten and a half months. It is also a personal experience. After practicing swimming for so many years, the only way to not grow muscles is to swim slowly. There are 50 100 people in the upper reaches of the Olympic Games, and their muscles are different. Breaststroke and butterfly stroke have strong shaping effects on pectoralis major and deltoid muscle, while freestyle and backstroke have shaping effects on biceps and triceps.