3) The athlete or client will use the rectus femoris to create hip flexion. This is the mysterious “quad pull” seen in sprinters or on forty-yard dash day in football. In this case the etiology is the same as above, only the culprit is now the rectus femoris, not the TFL. It should be noted, that most “quad pulls” or “quad strains” are limited to the multi-joint rectus femoris. Soreness will generally be near the insertion point of the rectus femoris into the quadriceps at about the mid-point of the thigh. The psoas and iliacus are to the anterior hip as the glute is to the posterior hip. A weak glute max will cause synergistic dominance of the hamstrings and extension of the lumbar spine to compensate for hip extension. This will lead to back pain, anterior hip pain (another Sahrmann point: use of the hamstring as the primary hip extensor changes the lever arm of the femur and can cause anterior capsule pain), and hamstring strains. On the literal opposite side a weak or under-active psoas will cause back pain from flexion rather than extension, TFL strain and rectus femoris strain.
Sit on the floor with your legs straight out in front of you. Bend your left knee so that your knee, shin, and foot are on the floor, parallel with your pelvis. Bend your right knee and place it on top of your left ankle so that your right knee is above your left ankle and your right ankle is above your left knee. To intensify the stretch, place your hands in front of your legs and very slowly walk them out as you lean forward. Stay relaxed and breathe. Repeat with the other leg.
So, who cares right? Wrong. Everyone has seen that little old man walking with a cane, hunched over almost to the point of staring at the ground. Do you think he always walked like that? I'd bet you he didn't. Maybe he had an injury that never healed properly, or maybe after spending years and years in a similar position, his body became tighter and tighter until eventually he ended up bent over.