|Butkus on a Nautilus Machine|
Working out on unstable platforms such as balance pads and exercise balls actually create more joint stiffness because muscles on each side of the joint are firing to stabilize it. You won't see a day in the gym go by without seeing someone doing a "Plank". Planks cause the muscles around the spine to work real hard to stabilize it which can be a good thing as long as you never move. Problem as you may be thinking...in real life we actually have to move around! Balancing on a squishy pad does work the muscles in the ankle and make them very stiff, there again as long as you never move this is a good thing.
Moving forward you can go a long way to having better core strength and balance by getting the muscles of your core and legs very strong through weight training. If you need better balance, include standing on one leg but on the ground and not a pad of any kind. It's just not needed. I'm excited to see the industry getting back to what actually works and away for the trendy crap that doesn't. Get strong as hell by weight training and the rest will fall into place. It's really that simple!