37 of 38 people found the following review helpful
There are two main reasons to get one of these. The first is if you want to strengthen your hand and arms. The second? To have fun!
First reason one. If you're looking for a way to strengthen your arm and hand, the powerball will definitely help you with this. Specifically, you have to hold on to it, so it works the gripping muscles of the hand. It also works the wrist muscles, because you have to rotate your wrist to keep the motion going. Lastly, your biceps will get a workout as well, because your biceps muscle helps turn your palm up (supination), which is one of the motions involved in keeping the gyro spinning.
I can't really see anyone with an acute… Read more