I have tried both methods and the results are good. 1 Hold a dumbbell or a bottle filled with water (or sand) and straighten it from front to back. Remember to do this next to your ear. 2. Put it down slowly and repeat this action fifteen times. When you finish, your upper arm will feel sour. That's right. Do it forty-five times a day, separately. The second secret recipe of thin arm: the right arm is extended high, the left scapula bends backward, the left hand presses the joint of the right arm, touches the left scapula, then extends high, and changes sides. This action is done 20 times a day. If you feel sore from the beginning, it means you have moved to that part. Sit-ups are necessary, and it is very useful to do more stretching exercises of limbs. Used on the back. After doing this for 2 months, the slimming effect is good. I am a sister, hahaha.