CanDo exercise balls are used by physical therapists as an aid for vestibular movement and equilibrium therapy, by fitness enthusiasts as an aid for stretching and strength training, and even by pregnant women in birthing classes. They are great for all ages, men, women and children. Underinflate to give the ball a soft, mushy feel, or inflate it to its max for a firm bouncy feel. The exercise balls have a 300 lb weight limit. On the initial inflation, inflate the ball, wait 24 hours, then add more air to fill the all to its maximum size.