I’m interested in using the half balls underneath a snowboard, so I may want the 5″ and 6.5″ half balls as well. I’d like to experiment with using them to create a rocker and also maybe combining two different sizes of balls or half balls to give a “downhill” rocker feel. Have you had any experience with this setup if so how well does it work? What combination of half balls or half balls/balls is a good “downhill” setup.
For snowboarding there are a couple of great things to do for the downhill effect. What we’ve done is placed a board on a stair step using the two half-balls. A half-ball on the ground and a half-ball a few steps up. I would just be careful of your snowboard flexing too much if you are standing in the middle and the ends are supported. I’ve done this with a wakeboard and our Ultimate Fitness and it was great. We used either a set of stairs or a small step stool- as long as it is stable. The smaller half-balls are great to fine tune your balance where the larger ones really get good range of motion and strength. You can use different sized half-balls also and play around with the tilt. Riding on two different sized balls is pretty challenging too. The top leg gets more strength because of the weight distribution, you just have to watch your foot stance and keep from sliding off the board.