You need to use sports equipment dumbbells, and you can have two dumbbells at home. When training, your feet should be shoulder width apart, hold dumbbells with both hands, bend over and straighten your back, so that the upper and lower bodies are 90 degrees or slightly larger. Then lift the dumbbell, bend your elbow to your waist, and then slowly put it down. Don't push the same arm down completely, leave a little angle, the arm is still exerting force, and then do the second one. This can also be divided into groups, one group 15, each group interval 1 minute, and relaxation and pull-ups are performed at intervals. We can also do it with one arm as shown below, and then alternate left and right hands.