This is yet another exercise that was conjured up due to lack of equipment at a commercial gym. As we know, most commercial gyms have a Bosu ball, so get some use out of it!

Place the Bosu ball round side down. Hook your heels under something or have a partner hold your heels down. Start in a fully-extended, legs straight position. Using your hamstrings, pull yourself as high as you can. You probably won't get very far, as it's more like a poor man's glute ham raise or inverse hamstring curl. Hold at the top for 2-3 seconds isometrically, then control yourself back down. Repeat for desired number of reps.