The function of the psoas major is another area of controversy
and uncertainty in the literature. It is well established
that the psoas functions as a primary flexor of the
hip joint6,10–14 but it is the other actions that are not well
understood. There are several hypotheses that have been
put forward that are worthy of consideration.
The electromyographic work of Basmajian11 was the
first to investigate the role of the iliopsoas. He concluded
that the psoas major could not be separated from the iliacus
with regards to their collective action of a hip joint
flexor. Keagy et al.15 performed electromyographic studies
on the psoas major in five patients with wire electrodes