Sick of doing crunches? Well here's a great exercise to work your abs and core using an exercise ball — no crunches needed. Start slow and work your way up to a higher number of reps. This exercise requires proper form to avoid injury and to get the full benefits. Here is how you do it:

• Begin by kneeling with the ball in front of you and with your hands on the ball.
• Walk your hands out on the ball just a little bit so your fore arms are resting on the ball. You should really feel your abs working, this is how you know you are in the starting position.
• Now slowly lower your body by rolling the ball out even more (away from your body), keeping your abs tight so you don't fall.
• Hold the furthest position you can go comfortably (without compromising form) for a couple seconds and roll back to starting position.
• Slowly return to the starting position by contracting your abs. That completes one rep.
• Do three sets of 5-8 reps.

Fit's Tips: Don't allow your back to hyper extend, keep your spine in a neutral position. Also, I like to place a towel or mat under my knees to cushion them a bit. And for an extra challenge, bring your feet off the ground and balance on your knees while doing the exercise.