The concept of time in each group is very important. The number of times is the maximum number of times that each group can complete a certain weight of dumbbells. A group of less than 6 times is used to improve strength; 8- 12 times to increase muscle mass; 15-25 times or more for improving muscle separation and carving muscle lines; Reduce fat by more than 25 times.

Usually beginners can practice three times a week, intermediate practitioners can practice three or four times a week, and high-level athletes can practice even twice a day during the season. Because the experiment shows that after an intense heavy exercise training, the physical function will drop for 2-3 days, recover to the original level in 3-5 days, and recover excessively in 5-8 days! Therefore, many high-level elite athletes only train each muscle group once a week for routine training.