1. Shoulder: Hold the dumbbell with both hands on the side of the body, with both elbows extended, palms facing forward, push the dumbbell in an arc to the highest point, and slowly lower the dumbbell. Do it with both arms at the same time, or rotate with one arm. You can also hold the dumbbells in two hands and hang them in front of your legs, lean forward slightly, bend your elbows slightly, lift the dumbbells to the shoulder height on both sides, so that the deltoid muscle muscles are tense, and then the strength of the shoulder muscles can be slowly restored.
3. Biceps brachii: You can hold dumbbells with both hands on your side, palms facing each other, elbows close to both sides of the body, and use the elbow joint as a support point to bend and lift upwards. You need to rotate the forearm outward and maintain a palm up position, raise it to the highest point, tighten the biceps, and then control the reduction.