Trainers Recommend Using a Big Exercise Ball. Using a stability ball will improve the strength of your core. Since a big yoga ball is unstable, you use your bodys core strength to remain balanced, which in turn improves proprioception, posture, flexibility and body alignment. Workout ball. Choose the perfect size of stability balls for exercise, whether a small exercise ball, like a kids yoga ball or a larger physical therapy ball. These sturdy workout balls for exercise come in 45, 55, 65, 75 and big 85 cm diameters, 55cm exercise ball, 65cm exercise ball and 75cm exercise ball (or 30 inch exercise ball) being the most popular. You can choose from multiple colors: slate, mist, mint, turquoise or sky. With this balance ball for exercise, you can get trim and toned by exercising ab, back, glutes, hips, arms and more making it the ideal full-body tool. Use as a balance ball chair (medicine ball chair) at your desk or office, for rehab, or during maternity as a pregnancy ball exercise for labor. Use the large yoga ball (or small yoga ball) for stretching, toning, balancing or various resistance exercises. The large exercise ball works great as a replacement to your home office chair, since as a yoga ball office chair, it is soft, engages the core and is at an ergonomic height. Yoga Ball Chair for Office. Swiss balls for exercise have found their way into the office as an office ball chair, turning sitting into a way to build your core strength. Burn more calories with the desk ball chair by performing active sitting. The big ball ab ball has become an essential birth ball for pregnancy and labor. Get your exercise ball for pregnancy and help reduce aches and pains caused by PGP and SPD. Increase your odds of a safer and faster birth with a labor ball. Should it burst or leak or the yoga ball pump break we will refund you for the life of the core ball for exercise. Get your excercise ball, maternity ball or sitting ball today!