This sounds like a glute stretch to me, but i'm no doctor. Leaning forward, ie, bending over, entails stretching your hamstring, glutes, and back.
The stretch i do that is similar to yours PN is this
I do mine next to a bench, chair, or my bed and in this case i would put my right hand on the bed, and only my left hand on my knee and vise versa. My chiropractor showed me this stretch a year and a half ago and it's done wonders. I do it along with a quad stretch and of course, ham string stretch.
I would agree that hamstring under development ie, muscle imbalance would be a good area to focus, just make sure you stretch both muscle groups regularly, but not to often, and never when you're cold.
I find the best time to stretch is right before i got to bed every night.