Okay, so I'm going to go over a Swiss ball seated curl with you today. Now, this is just like your every-day dumbbell curl, standing or seated, only you're on this ball. The whole thing that this ball adds is instability, so you've got to work your core to stay stable during this exercise. It's going to be just like your average dumbbell curl. You're going to start with your palms facing you. Come up, rotate your wrists, squeeze that bicep, return with control and alternate.
You can do them together as well. The idea of this is to keep your feet firmly planted and really use your core to stabilize you. Come up, use your core to keep you in place, rotate your wrist as you come up, squeeze that bicep, and return back down with control. Same thing with the other arm. Now, with this it could get very dangerous if you're not smart about it. If you're swinging the weight, if you're rocking the ball, many things could go wrong, so it's a very controlled exercise. The more controlled the better results you get anyway.
Again, it's up, squeeze, down, return. You're working your biceps completely, working your core as well, and because it's a little wider than normal, you're going to feel it in your shoulders. Okay? So it's really, really working your upper body to a whole different extent than just sitting on a regular flat bench. Breathing-wise, you always want to breathe out when you're working against gravity. So when you're pulling up against gravity, breathe out, inhale, exhale, squeeze, inhale.
Make sure not to swing; make sure not to cheat the exercise. Work your biceps with the full range of motion. Don't be doing half-reps - that's a different kind of thing. You want to make sure that you come all the way down, not locking out your elbow, but keeping a slight bend. Up, squeeze, elbows are going to remain at your side. If you're bringing them out here to curl that up, you're using leverage and you're cheating the exercise.
Keep that elbow down, squeeze that bicep, and return with control. Return with control. And that's the Swiss ball dumbbell curl.