Method 1:

Chest muscles: On a supine bench, pushing with dumbbells horizontally, obliquely upwards and obliquely downwards is more beneficial to muscle growth than using barbells, because it can stimulate muscles more widely and deeply. You can also do multi-angle bird exercises with dumbbells to develop all parts of the chest muscles. A good practice method is to do a set of dumbbell bench press exercises immediately after finishing a set of dumbbell flying birds. This kind of exercise is not only effective, but also can reduce the burden on shoulders and avoid sports injuries.

Method 2:

Abdominal muscles: lie on your back, put the dumbbell behind your head and sit up to practice the upper abdominal muscles; Abdominal contraction and leg lifting (upper body motionless) can exercise lower abdominal muscles.