This exercise targets the obliques and is great when using a moderately heavy weight to add extra challenge. You will need one powerblock or dumbbell.
Stand with you feet about shoulder width apart holding the weight in one hand at your side. Your stationary hand can rest on your hip (I like to place it a little higher so I can feel my obliques working). Slowly lower the weight about a half foot, then bring it up and crunch your obliques. Once you finish with this side, switch them and repeat.