About 40 minutes is best. ? Morning running (jogging) is a low-intensity exercise, which has limited help for muscle growth. Only for people who are particularly lacking in exercise (muscles are usually unhealthy, lifeless and wilting), the initial exercise stimulates the vitality of muscles and will increase a little muscle (just from very garbage to general garbage, a small amount); After more practice, the muscle circumference will not increase greatly, even because exercise reduces the fat between muscles, but makes the leg circumference thinner (long-distance runners are a good example).
As long as you pay attention to warm-up before running and stretching after running (stretching is very important for not thickening your legs), it is almost inevitable to make your legs more stylish and thinner (unless you are born thin and have no meat, stovepipe will become bodybuilding and you can't lose weight). Of course, exercise is closely related to diet and work and rest.
In short, jogging has a great effect on reducing fat and stovepipe, and it will increase muscle for fat people, especially for extremely thin skeletons.
However, you need to run in a planned way. After you can exercise easily for an hour, we can change the training mode by running at different pace, such as sprinting and variable speed running. Short-distance anaerobic accelerated running can burn a lot of fat in the body quickly, and physical fitness needs more supplies. The training mode of jogging and sprinting can achieve a good fat-reducing package and solve the psychological and mental fatigue of long-term jogging training.