I find it hard! Apparantly Contracted-position hip hyperextension movements such as SL back extensions cause the highest mean and peak hamstring activation yet when i try to do them my spinal erectors give out WAY before i can even feel my hamstrings working. I tried doing them 1st in my workout and had to end it short as I couldnt continue my workout due to the intense pain in my lower back. Im also 197cm tall, does this have anything to do with it? A lil help would be much appreciated