The iliacus and psoas major muscles arise from the pelvis and lumbar ... should be on the ground. The leg being stretched should be positioned forward to allow the hip to extend.

uq.edu.au Objective In this study, asymmetry relative to the preferred kicking leg was determined if it exists for the psoas and quadratus lumborum muscles among elite Australian Football League (AFL) ...

Together, the iliacus and the psoas make up the hip muscle group that connects the spine with the inner hip. Essentially, it is these two muscles that kick into gear when you lift your leg.