CONTRIBUTION OF ILIOPSOAS AND QUADRATUS LUMBORUM MUSCLE SIZE ON LONG DISTANCE RUNNERS
A hypertrophy of psoas muscle (PM) is assigned to be one of the major determinants for sprint running [2] Moreover, the erector spinae and quadratus lumborum muscles related to the sprint performance [3] These results suggest that higher sprint performance require the stabilization of the trunk lateral movement. The main function of PM is to flex the thigh on the pelvis, but also counteract as lateral flexion of the lower vertebral column. The functions of quadratus lumborum (QL) was considered as lateral flexion of lumbar spine. Therefore, activating unilateral PM with complementary activating contra lateral QL can stabilize the lumbar spine during running.