This style of lunge is actually slightly better than the forward lunge when it comes to building muscle, partly because it's harder to compensate with the lower back, so your form is better.
If your goal is to build your quads, this reverse lunging style also beats the forward lunge, which is better for glutes and hamstrings.
Five wins by TKO, four wins by submission, three wins by decision... and a single loss to Matt Hughes by armbar in his first title fight. It's that last one that haunts Spike athlete Georges "Rush" St-Pierre.