A single-leg squat is a rear-foot-elevated split squat done on a high surface like a bench rather than a step. It’s a great exercise to stretch the hip flexors, but you can heighten the effect by extending the arm on the same side as the elevated leg, and by holding a weight. I call it the “statue of liberty” squat.

To really impose a stretch on the entire fascial line, place the top of the foot on the bench (where your shoelaces are) and extend the wrist back – a kettlebell works well for this. It may not correct years of sitting, but it sure won’t hurt. (Actually, it may hurt a bit!)