The iliopsoas, also known as the iliac psoas or simply “the psoas,” is a muscle that has gained attention due to its involvement in numerous painful and/or dysfunctional conditions, including the well-known low back pain.
Because of its extensive span—from the lumbar region of the spine to the femur—the iliopsoas plays a crucial role in movement. It is the primary hip flexor and an important stabilizer of the spine.
By structurally connecting the trunk and pelvis to the lower limbs, it is subjected to multiple mechanical demands, often leading to muscular and postural issues that affect a wide population, from sedentary individuals to athletes.
Anatomically, the iliopsoas consists of two muscle bellies: the psoas major and the iliacus. They originate respectively from the lumbar vertebrae (including the last thoracic vertebra) and from the pelvis, then merge in the lower trunk and insert into the lesser trochanter of the femur.
Its function is easy to understand: in addition to being the primary hip flexor, the iliopsoas contributes to anterior and lateral trunk flexion. From a postural perspective, it stabilizes the lumbar spine and supports the
maintenance of lumbar lordosis and thoracic kyphosis.
Common causes of iliopsoas dysfunction include a sedentary lifestyle, which leads to shortening and weakening of the muscle, promoting pain and stiffness. Prolonged sitting creates constant contraction, which may result in low back pain.
Excessive physical effort and intense activities involving repeated hip flexion (such as running and cycling) can overload the psoas muscle, increasing the risk of contractures, strains, or injuries.
Poor posture may also cause abnormal muscle tension and biomechanical dysfunction of the iliopsoas and the entire lumbar spine, resulting in pain and stiffness.
Traumatic injuries to the lumbar or pelvic region can damage the psoas muscle, while muscular imbalances—by altering force distribution between the hip and spinal muscles —often lead to psoas overactivity, causing low back pain, hip pain, and pelvic discomfort.
Symptoms
Common symptoms include low back pain in the lower spine, which may radiate toward the abdomen or groin; stiffness and difficulty with movement; groin pain that may radiate to the anterior thigh; reduced mobility; and compromised posture, such as a forward-leaning position (reduced lumbar curvature) or difficulty maintaining an upright posture for prolonged periods.
Kinesiological treatment
Muscle strengthening exercises combined with stretching and lengthening exercises represent the first therapeutic option. Strengthening exercises help the muscle respond to load demands that exceed its resistance capacity and reinforce the stabilizing muscles of the spine and hip, which are essential for preventing recurrence.
A specific stretching program can help relieve tension and improve flexibility. Joint mobilization—particularly of the lumbar and pelvic regions—helps reduce pain and supports the tensile forces applied to the muscle during work or sport.
Correcting posture and daily habits is essential to prevent shortening of the psoas muscle and related pain. If left untreated, iliopsoas dysfunction can lead to chronic pain and functional limitations. Regular physical activity plays a key role in preventing muscular dysfunction.
In cases of persistent or acute pain, it is important to consult healthcare professionals for an accurate diagnosis.