That's the One-Leg Lunge in a nutshell. You should have a couple of training partners to stand by when you make your first experiments, just for safety. You should also begin this exercise with a very light barbell until you become accustomed to it balance wise.

Oh, you'll wobble and weave quite a bit at first. But don't worry. Before your first training experiment has ended there will be a big improvement and almost before you know it you'll be raising and lowering yourself just like a veteran!

Although I suggested that you hold the bar at the back of the neck there's no reason why you shouldn't make some experiments with the bar held in front of the neck. Squat style lifters and leg split lifters would both benefit enormously by practicing those variations providing that they remember to make alternate sets with the left and right leg to the front.