The 55cm two-tone grey and blue Reebok Gymball is one of the most versatile pieces of exercise equipment for improved all-round fitness, used to perform a wide variety of exercises which will considerably improve your core strength, posture and flexibility. Its weighted base provides additional grip and helps to stop the ball rolling away during every type of exercise. Though they may appear the same, gymballs come in many diametrical sizes and materials, so it's important to choose the right exercise ball for you. The 55cm stability Reebok Gymball has been manufactured with a high-density rubber to ensure longevity, and is suitable for those between 155cm and 167cm tall (approximately 5'1 - 5'6" feet). Selecting the appropriately sized gymball for your height is extremely important in ensuring you get the most of out of your workout. By observing the '90 degree rule', (where both feet are planted on the floor and knees positioned a little lower than the pelvis, making a 90 degree angle), you'll discover your ideal gymball size. It's also important to note that your height alone isn't the only factor in determining the right ball size. As Reebok exercise balls are flexible and offer resistance, weight is also an important factor. Supporting your ab crunches, tricep dips, planks and stability work, the two-tone gymball features anti-burst technology, meaning if the ball happens to puncture during your workout, it will slowly and safely deflate to avoid any possible injuries. Every Reebok Gymball ships with its very own kit including the fundamental pump. And, if you're in need of a little inspiration to kick-start your gymball workout, this stability gymball comes complete with its very own workout DVD. ◾Ideal for sit ups, core strength, stability and general fitness ◾Includes workout DVD and gymball pump ◾Suitable for those between 155cm and 167cm tall ◾Two-tone stability Reebok Gymball from the Reebok Women's Training range - 55cm in diameter ◾Weighted base provides additional grip and helps to stop the ball rolling away during exercise |