I LOVE them!
I bought two at IDEA 2012, a classic and a Pro. They look deceptively harmless, lol, but they pack a punch!
What I like about them is that you have to stabilize all of your joints except for the one or two that are causing the blade to move. So, for example, I can put someone in a back stance (a simple martial arts stance with more weight on back foot than the front, back leg turned out) and have them squat down a bit in that, then punch front and back, vibrating the blade in the saggital plane. They’re stabilizing around the hip, the core, the trunk and the shoulder, and they’re feeling fire in the biceps, triceps and shoulder!
Another thing I really like is that it’s very hard to get injured with a BB. You’re using your own mobility to get the blad moving. It’s very lightweight, only about a pound and a half. And the movement on the joint is gentle because the way the blade oscillates it decelerates your movement in one direction before you move in the other direction. I have arthritic clients that can use the blade better than other handheld equipment.
I use them in my Tabata classes and in my CrossCore(r) classes. They’ve gon over so well that I invested in another Pro, 3 more Classics, and two XTs. So now everyone in my small group has one they can use. We look like a flock of geese, lol, but we’re happy, functional, STRONG geese!
If you have any more questions, I’m happy to answer.