1.  Stand on the platform facing the weight stack. 
2.  Slip foot into harness. 
3.  Hold onto support bar and stand straight with both knees slightly bent. 
4.  Keeping the upper body and standing leg stationary, bend knee, bringing heel toward glutes. 
5.  Maintaining tension on the muscle, return to the start position and repeat movement.

Primary Muscles

Hamstrings, Plantaris, Gastrocnemius