Our Everlast ball (55 cm diameter) is suitable for people from about 5'6 feet to 5'8 feet . The important thing is that you are well positioned in your exercises, and that your hips are slightly higher than your knees, once you are seated on it. Sitting positions at 90 degrees will never be comfortable for anyone.
**the following standards are established for information purposes only. And everyone has their own needs, especially in terms of comfort.**