They note the activity of rectus femoris to be more prominent than the remaining vasti portions in high-speed movements. They also point out that its activity increases вЂwhen heavy loads are carried on the back, when walking speed is increased, and when one wears high heelsвЂ™. Though it is not active in quiet standing, the quadriceps femoris is active in backward bending, sitting down from standing position, descending stairs and in squatting. Travell & Simons (1992) note that when the foot is in a fixed position, the pull of the quadriceps femoris is focused on the proximal end to control the influences of body weight at the pelvis. Shortness and tightness of the rectus femoris is frequently associated with tightness of the psoas muscle and can restrict the anterior capsule of the hip jointвЂ¦a major problem in the gait results from tightness of the psoas and rectus femoris anteriorly and weakness of the glutei posteriorly. Greenman (1997) observes that when rectus femoris is dysfunctional, it becomes:ДЇacilitated, short and tight the other three components of the quadriceps groupвЂ¦ вЂ¦ when dysfunctional, become weak. At the very least, the likelihood of a false-positive standing flexion test should be kept in mind if there are hamstring influences of this sort operating. The hamstring length test as described in Chapter 12 should therefore be carried out first and if this proves positive these structures should be normalized, if appropriate, prior to use of the assessment methods described here. there may be iliosacral motion that is masked by the restriction placed on the ilia via hamstring shortness). ДЇalse-negative results if there is bilateral hamstring shortness (i.e.ДЄ false-negative result ipsilaterally and/or a false-positive sign contralaterally if there exists unilateral hamstring shortness (due to the restraining influence on the side of hamstring shortness, creating a compensating innominate movement on the other side during flexion) or.To determine if one PSIS is superior or the other inferior, each should be compared to its paired ASIS and normal would be indicated by an ASIS and a PSIS, on the same side, being level (or almost level) with each other.Д¬AUTION: The evidence derived from the standing flexion test as described below is invalid if there is concurrent shortness in the hamstrings, since this will effectively give either: Superiority of one PSIS may indicate rectus femoris, TFL, anterior gluteal or iliacus shortness and involves anterior tilt of that innominate around a horizontal axis. Inferiority of one PSIS may indicate hamstring shortness or pelvic/pubic dysfunction and involves posterior tilt of that innominate around a horizontal axis. ДЄnteriority of one PSIS may involve shortness of the external rotators of the ipsilateral leg (iliopsoas, quadratus femoris, piriformis) or contralateral internal rotators (anterior fibers of gluteus medius, tensor fasciae latae, hamstrings) and involves a rotation of the pelvis or innominate around a vertical axis.Is one superior, inferior or anterior to the other? The PSIS positions are assessed just below the pelvic dimples.

Anterior superior iliac spine