1, the weightlifter holds a pair of dumbbells, with his knees slightly flexed and explosive force upward, pushing the dumbbells up to his head. Keep the core tight throughout the process and don't bend back. Complete three groups of exercises, and each group will do 15 times. 2. Push the dumbbell with one arm to sit in a sitting position, grab a dumbbell with both hands backhand, lift it to the shoulder source, inhale, then lift the left and right arms alternately, and turn the wrist to make the palm face forward at the same time, and exhale after the action is completed. Complete three groups of exercises, with each group holding hands 15 times. 3, sitting posture triceps dumbbell lift bending one arm dumbbell arm flexion and extension, need a chair as the support of the other hand. In practice, the upper arm of the bell-holding arm remains motionless, and the triceps brachii is straightened backwards with the forearm on the elbow joint as the axis. Complete three groups of exercises, and each group will do 15 times. ?