Prone Leg Curl.

Face down. Hips out of play.

The back of the thigh is the part you notice first when it goes. Lying face down, the hip is out of the picture and the knee has to deliver alone, no little swing, no momentum into the rep. The pad under the hips keeps the pelvis in place so the lower back is not allowed to join in, and with 100 kg in the stack you can treat the hamstrings as a muscle you actually build. Floor space 1595 × 1100 mm, dead weight 216 kg. The hamstrings get no help from here.