Becky Keller on Instagram: "If you feel hamstring curls more in your lower back than your hamstrings, it’s usually a setup issue. Here’s an easy fix. Place a foam roller under your hips when using the prone hamstring curl machine. Why it works: Slight hip flexion puts the hamstrings in a better position to produce force. It limits excessive low-back arching so your spinal erectors don’t take over. It also keeps your pelvis more stable, helping you isolate the hamstrings instead of compensating.