Because they’re like very strong balloons, the balls create a slightly unstable surface, which causes you to engage more muscles when you work out. “One of the reasons the ball is especially good for people with RA is you strengthen the small muscles that help stabilize the joints just by trying to keep yourself balanced,” says Scott Haak, a physical therapist at the Mayo Clinic in Jacksonville, Florida.
Lightweight and versatile, fitness balls can be a great start to a home gym. Not much research has been done on the balls, especially among nonathletes, but a few small studies point to their benefits.
Sixty people with ankylosing spondylitis who performed a series of exercises on a ball twice a week for four months improved muscle strength and walking performance more than a control group, researchers reported in the Brazilian journal Revista Brasileira de Reumatologia.
Thirty-six healthy young adults doing balancing exercises on a Swiss ball improved both static and dynamic balance, Korean authors found in research published in the Journal of Physical Therapy Science.
And research published in the Journal of Strength and Conditioning Research conducted in 44 people over 65 concluded that three months of exercising on a ball improves posture, gait, and balance.