Gluteus maximus has a major functional importance in
the early stance in walking and generates most of the support
and prevents collapse of the hip, knee and ankle. Loading response is characterized
by the free fall of body gravity and 60% of the body
weight is transferred in 0.02 s, resulting in abrupt loading
of the forward limb. It is at in this moment that the gluteus
maximus compresses the sacroiliac joint to provide stability. The inappropriate activation
of the gluteus maximus in gait is thought to be a cause of
low back pain, resulting in a deficiency in the shock absorption
mechanism at the sacroiliac joint. Biceps femoris has been shown to have an early
onset in sacroiliac joint pain subjects , and is thought to be a compensation for the weakness
of the gluteus maximus