The neutral-hip Nordic hamstring curl is the most difficult NHC variation. Of course, placing the hands behind the head or wearing a vest would make the exercise more challenging, but the majority of lifters will never make it to that level of strength. Keep the hips and pelvis in neutral throughout the movement and lower the torso under control.

Related:  The Best Way to Build Your Butt

Related:  The Best Damn Posterior Chain Exercises