by Christian Thibaudeau

BOSU ball curls are idiotic. Why? Well, you simply can't lift as much weight when you're on an unstable surface. And you lose a lot of the mind-muscle connection when your attention and CNS resources have to be divided into two different motor tasks. As such, you're losing both the capacity to overload the biceps and to improve the mind-muscle connection when you add the BOSU ball to the equation.

"Yeah, but you're improving stability and core strength!” Maybe. But there are better ways of doing that. And those methods don't involve making another exercise (curls) less effective. In the end, you have an exercise that makes the curling portion largely ineffective at building the biceps, and a balance drill for which you're not ready for. Great combo, huh?