|Utility:||Basic or Auxiliary|
Sit on floor facing suspension trainer loops in low position. Grasp bottom of loops, then lay supine. Raise legs and place heels in loops with soles contacting handles. Extend legs out and place arms on floor off to sides. Straighten low back, knees, and hips, raising back and hips off of floor.
Pull heels toward rear end by bending knees and hips simultaneously. Lower body to original position by straightening knees and hips. Repeat.
This exercise can be performed on TRXⓇ style suspension trainer. See Suspended Supine Feet Mount/Dismount. Keep low back straight, maintaining approximate height from floor throughout movement. Hamstrings seemingly acts as a dynamic stabilizer, since it shortens through knee, while it lengthens through hip. However, net contraction actually appears to occur, since hip flexes only about 50%, while knee flexes nearly 100%, allowing hamstrings to remain in a mechanically strong position throughout movement.
Apart from Sartorius involvement, flexion of hips is largely passive and is accomplished by eccentric contraction of glutes during concentric contraction of hamstrings, even when lying far away from suspension anchor.
Movement can be made easier by lying closer under anchor of suspension trainer.
Movement can be made more challenging by lying further back, away horizontally from anchor of suspension trainer. Alternatively, hips can be kept straight during knee flexion increasing active insufficiency of hamstrings.