The first thing you must do when choosing an exercise ball is to find the right size for you. This depends mainly on your height, but you must also take into consideration whether you have long legs or long body within the overall height.
Sit on the ball firmly and note the bends at hips and knees. Your hips should be level or slightly higher than your knees. This means that both will be bent to 90o with your thighs parallel with the floor.
It may be that you will feel more comfortable exercising with a slightly larger exercise ball. This is fine. Just don’t get one that is too small as it will not offer enough stability.
Here is a rough idea of the sizes available and the heights for which they are suited
45 cm (18 in) – less than 5’0”
55 cm (22 in) – 4’11” – 5’4”
65 cm (26 in) – 5’5” – 5’11”
75 cm (30 in) – 6’0” – 6’7”
85 cm (34 in) – 6’8” and up
These are very general guidelines. Don’t forget to take into account whether you have long or short legs for height. If you have back problems it may be better to have larger ball.
Size of ball and firmness depends on what you want it for – stretching, weight training, yoga, Pilates or just to use as a chair. If you want a soft rather than firm ball choose the larger size.
Worried that you are overweight/obese? Burst resistant balls are made to hold 600 or more pounds. So look into this aspect too if need be when choosing an exercise ball.
