Choosing the size of a yoga ball depends on one's figure. Yoga balls have diameters of 30 cm, 45 cm, 55 cm, 65 cm and 75 cm. Men should choose the older ones, and women should choose the smaller ones.

For example, a petite lady can choose a 45cm or 55cm yoga ball, a tall man can choose a 65cm or 75cm yoga ball, and people who are overweight and have long arms should choose a bigger ball to practice.