First, build big muscles first. This is a training principle that should be followed. Don't indulge your temper, pick up your equipment and practice at will. The muscle groups of legs, chest and back belong to large muscle groups, and the exercise of these muscle groups requires a lot of load, otherwise it is difficult to achieve results. Therefore, when you are energetic and can overcome the heavy load, you should first practice these muscle groups. If you wait until the end of the training class to practice these muscle groups, you will be at a loss, the effect will be greatly reduced, and even an injury accident will occur. For example, people often start training by doing three sets of bench press exercises with a 90kg barbell, and then do three sets of triceps push-down exercises with a 30kg barbell in the second half of the class. One day, he reversed the training sequence, and first did the triceps push-down exercise with a 34 kg barbell. When practicing bench press, he could only push up a 79 kg barbell at most. This is because the triceps has been trained with a certain load in push-ups, and it is too tired to complete the bench press of three groups of 90kg barbells. In this case, for the tired triceps, the weight of 79 kg is close to the limit load, but it is far from enough to develop the chest and shoulder strap muscles. Obviously, it is much better to finish more muscle group exercises first, and then complete single muscle exercises. Because using a smaller weight in a single muscle exercise will not affect other muscle groups, a single muscle itself can get a greater stress stimulus. Second, muscles should be trained alternately, which is also a training principle. Don't practice the same muscle continuously. The muscle groups that practice alternately can recover to a certain extent after each exercise, so they can bear a relatively greater load every second exercise. Because the development of muscle strength and volume is closely related to training intensity, alternating exercise is more conducive to the growth of muscle volume and strength. For example, bench press and triceps push down, triceps is the driving force. Practitioners can overcome the resistance of 30 kg by doing triceps push-down exercises immediately after bench press. If he completes a set of elbow flexion and extension exercises between the two groups, he can overcome the resistance of 34 kilograms when doing push-down exercises, because the tired triceps recovered to a certain extent. If the trainer intends to stimulate the same muscle continuously, it should be noted that the recovery interval must be long enough.