Ahhhh, hamstrings. For some of us, it seems like they tighten up no matter what we do. They talk back whether we are sitting squatting, running, biking, or lifting weights. On the other side of the spectrum, those of us who are fairly mobile (whether naturally or through doing lots of yoga) might have little to no feeling in the backs of our legs. Either way, it's time to bring these key muscles more fully online, because incorporating yoga moves that both stretch and strengthen this area will have you standing taller and moving with more grace, power, and ease in no time.
Pro tip: focus the stretch on the belly of the muscle rather than at the attachments (your hamstring attachment points are at the knees and sitting bones). If you feel pulling in either of these areas, back off by bending your knees slightly and engaging your core a bit more diligently.