Steps/methods
1. Keep your feet shoulder width apart. Hold the mineral water bottle with both hands and stretch horizontally to both sides, palms up, then turn clockwise for 30 times and counterclockwise for 30 times.
2. Then put your palm in front of you. The upper arm and the lower arm are fixed at an angle of 90 degrees. Focus on the biceps brachii on the front side of the upper arm, feel the muscles tighten, and lift your hands together or alternately.
3. Stand with your feet apart, hold the water bottle above your head with both hands, then lower your forearm backwards, keep your big arm close to your ear, and then slowly straighten your elbow up until your arm is completely straight. The key point is to tighten the triceps brachii, keep the movement slow and don't shake your body at will.
4. Hold the water bottle with both hands and straighten it to your chest. Bend your elbow with one hand and place the water bottle inside the elbow of the other arm. Repeat this action alternately with your hands.