Michelle Beaumont: I'm Michelle. I'm demonstrating a bicep curl with free weights on the ball, or you can call it a preacher curl. Preacher curls are difficult to do because they require fully isolating the muscle group. When you do a preacher curl you want to maintain good form, your arms are going to be hanging down, so you have no choice but to work from the bicep it doesn't give you a lot of extra arm strength. We are going to begin by placing our bellies right here on the ball, toes are behind you in a plank position. You do want to keep your chest slightly elevated don't totally collapse over the ball. If you are a beginner, you may bend your knees a little and move back and make this easier, or if you are more advanced you do want to challenge yourself and really come all the way out as far as you can, towards the ground squeezing in and out, inhaling and exhaling. If you are trying to build strength, you want to go with heavier weight and lower repetitions. If you are toning and shaping the muscle you may go with higher reps and lower weight. If you are a beginner you are obviously are going to start with lower weight and again in a modified position and that's it.