How to avoid yoga injuries: Hamstring pulls
Ironically, if you work too hard to protect your lower back — yet push deeply into a forward bend — you can pull your hamstring muscle up near your buttocks. Awan says people who go very deep into forward bends tend to do this. Instead, pull back. But also, breathe into the entire length of the hamstring along the back of the leg to be sure you’re stretching it all.