I recently purchased a dyna-flex gyro powerball from Amazon. Prior to purchasing it, I did get a chance to try it out at a local BIG-5 store. They had a powerball and the docking station for display and use to customers right in front of their cash register. I tried it out and all of my skepticism quickly went away. Let me tell you, I have a ton of joint issues from weight lifting like wrist tendonitis, tennis elbow (barbell curls) and rotator cuff soreness (bench press). My first impression was how much torque this little thing produces. It was as if the ball was trying to free itself from my grasp but when I held it and rotated my wrist, it helped created enough tension where my muscles were being put into play. I ended up not purchasing the item but when I drove home I suddenly realized that my wrist felt better and my natural range of motion in my wrist was coming back whereas before I couldn’t without some sort of soreness or tightness in my wrist.
After looking at other great reviews online I decided to give it a shot and bought it off Amazon. Every day I’d do a variety of arm motions with the powerball gyro spinning in my hand and after about a week my tennis elbow pain decreased dramatically, my rotator cuff was healed but what felt the best was my wrist having its range of motion back. Lifting weights at the gym requires my wrist to be strong and able to withstand jerking movements and ever since I have owned the powerball, my wrist never felt better. I highly recommend this product not just as a rehab tool but to prevent injuries in the future by strengthening the muscles that the powerball emphasizes.