The exercise of fitness ball seems simple, but in fact it changes greatly and achieves different effects. The following questions should be paid attention to when choosing and using fitness balls: 1. Choose a fitness ball that suits you according to your height and lower limb length. When choosing the ball, try to sit on it, with your thighs parallel to the ground, especially your hips not lower than your knees. 2. Beginners, people with heavy weight and poor balance ability should choose soft balls. 3. If the exercise space is limited, or it is only used in narrow areas such as offices, bedrooms and bedside, the hardness of the sphere can be ignored. 4. Exercise the fitness ball step by step. You can put the Swiss ball in a narrow space, such as against the wall or beside the bed, to reduce its rolling. Practice starts from a simple sitting position, gradually upgrades to a supine or prone position, presses the back or abdomen on the ball, and then does other actions. With the enhancement of balance ability, practice in spacious training venues. The movements are also gradually upgraded, such as changing from two-legged support to one-legged support, adding various gymnastics movements, and even combining dumbbell exercises with limbs. With the increase of difficulty, the strength and balance of the body have been fully exercised.