Psoas Strain

Lower Limb

Overview

Psoas strain is an acute or chronic injury to the psoas major muscle, typically resulting from excessive hip flexion, rapid acceleration-deceleration movements, or prolonged postural stress. This condition commonly affects athletes, desk workers, and individuals with altered lumbopelvic biomechanics. Pain is typically deep in the lower abdomen or groin with potential radiation into the anterior thigh.

Pathophysiology

The psoas major muscle originates from the lateral aspects of the T12-L5 vertebral bodies and intervertebral discs, passing through the pelvis to insert on the lesser trochanter of the femur. Strain occurs when muscle fibres are overstretched or experience excessive eccentric loading, particularly during hip flexion against resistance or rapid hip extension. Microtears lead to inflammatory response, haematoma formation, and subsequent muscle guarding. Chronic strain may result from sustained hip flexion postures (desk work, driving) creating adaptive shortening and increased tension. The muscle's deep anatomical position and proximity to visceral structures can complicate diagnosis and create referred pain patterns.

Patient Education

Psoas strain typically improves with relative rest, hip flexor stretching, and gradual return to activity; early movement within pain tolerance promotes healing better than complete immobilisation.

Typical Presentation

Site

Deep lower abdomen, groin, anterior hip crease; may radiate along anterior thigh to knee; symptoms often unilateral but can be bilateral with postural causes

Quality

Deep aching, sharp catching sensation with movement, constant dull ache with acute strain; may feel like abdominal discomfort or groin strain

Intensity

Acute strain: moderate to severe pain limiting hip flexion and walking; chronic strain: mild to moderate persistent ache worsening with activity

Aggravating

Seated hip flexion (desk work, driving), walking uphill, running or sprinting, rapid hip extension movements, direct abdominal pressure, lying supine with hips extended

Relieving

Prone lying or side-lying positions, hip flexion (knees drawn toward chest), gentle stretching, heat application, anti-inflammatory medications, osteopathic treatment

Associated

Limited hip flexion range of motion, anterior hip tightness, lower back pain, pelvic asymmetry, lumbar lordosis increase, altered gait pattern, hip flexor weakness on contralateral side, possible abdominal wall tension

Orthopaedic Tests

Thomas Test

Procedure

Patient supine on examination table with one hip and knee flexed (pulling knee toward chest to flatten lumbar spine). Observe for hip extension on the opposite side; if the extended limb lifts off the table, psoas tightness or shortening is present.

Positive Finding

Hip extension of the non-flexed leg (inability to keep extended hip on table) or increased lumbar lordosis during the maneuver

Sensitivity / Specificity

null / null

Interpretation

Indicates psoas muscle tightness, contracture, or adaptive shortening. Common in hip flexor tightness but nonspecific for acute psoas strain.

Modified Thomas Test (Psoas Emphasis)

Procedure

Patient supine at edge of table; both hips/knees flexed. Release one leg to hang off table in hip extension while keeping the opposite knee flexed to chest. Assess hip extension and knee flexion of the hanging leg.

Positive Finding

Inability to achieve full hip extension or knee flexion on the extended side; pain or guarding in the anterior hip/lower abdomen

Sensitivity / Specificity

null / null

Interpretation

More specific for psoas tightness or irritation than standard Thomas test. Positive result suggests psoas involvement in hip flexor restriction.

Psoas Stretch Test (Modified Ober's Position)

Procedure

Patient in side-lying position on unaffected side with hips and knees flexed. Extend the top hip and knee off the edge of the table into hip extension. Allow gravity to passively stretch the psoas of the extended leg.

Positive Finding

Pain or cramping in the anterior hip/lower abdomen; inability to tolerate full hip extension; muscular guarding

Sensitivity / Specificity

null / null

Interpretation

Reproduction of anterior hip or lower abdominal pain suggests psoas muscle irritation or acute strain. Useful for both assessment and treatment validation.

Palpation of Psoas (Supine)

Procedure

Patient supine; examiner stands at patient's side. Place fingers medial to the ASIS and press deeply into the abdominal wall at the level of L4–L5 (below the umbilicus) while patient relaxes. Palpate for tenderness or muscular tension.

Positive Finding

Localized tenderness over the psoas muscle belly; muscle spasm or guarding; reproduction of concordant pain

Sensitivity / Specificity

null / null

Interpretation

Direct palpation tenderness suggests acute psoas strain or myositis. Pain reproduction is clinically significant for confirming psoas involvement.

Resisted Hip Flexion (Seated or Supine)

Procedure

Patient seated or supine with hip at 90° flexion. Examiner applies manual resistance to anterior distal thigh while patient resists hip flexion movement.

Positive Finding

Pain or weakness with resisted hip flexion; patient apprehension; visible or palpable muscle guarding in anterior hip/lower abdomen

Sensitivity / Specificity

null / null

Interpretation

Positive result suggests active psoas strain or iliopsoas dysfunction. Pain with resistance is more specific for contractile tissue injury than passive stretch pain.

Pace's Test

Procedure

Patient lies prone or semi-prone. Examiner applies passive external rotation and abduction to the hip while monitoring resistance. Alternatively, patient actively resists hip flexion and external rotation from a prone position.

Positive Finding

Pain in the anterior hip, lower abdomen, or anterior groin; weakness with hip flexion and external rotation combined movement

Sensitivity / Specificity

null / null

Interpretation

Combines hip flexion and external rotation to isolate psoas function. Positive result (pain or weakness) is consistent with psoas strain or iliopsoas syndrome.

⚠ Red Flags

  • •Severe sudden onset with inability to walk suggesting complete muscle rupture
  • •Unilateral lower limb swelling and warmth suggesting deep vein thrombosis
  • •Fever and progressive systemic symptoms suggesting psoas abscess or infection
  • •Acute urinary retention or bowel dysfunction suggesting cauda equina compression
  • •Unexplained weight loss with persistent groin symptoms suggesting malignancy
  • •Severe unrelenting night pain suggesting serious underlying pathology

⚡ Yellow Flags

  • •Excessive work-related prolonged sitting without postural support
  • •Fear-avoidance beliefs about hip flexion causing hypervigilance and guarding
  • •High catastrophising about abdominal symptoms confusing diagnosis with visceral pathology
  • •Overtraining without adequate recovery in athletic population
  • •Poor body awareness and proprioception contributing to chronic strain
  • •Maladaptive coping strategies (complete immobilisation rather than graduated activity)

Osteopathic Techniques

Region

Psoas muscle and iliopsoas complex

Technique

Soft Tissue

Rationale

Direct soft tissue mobilisation to the psoas muscle via transabdominal approach (with appropriate pressure) or indirect techniques addresses muscle tension, promotes tissue healing, improves circulation, and facilitates neuromuscular re-education. Reduces protective muscle guarding that perpetuates dysfunction.

Region

Lumbar spine and lumbosacral junction

Technique

Articulation

Rationale

Gentle lumbar articulation restores segmental mobility restricted by psoas tension and associated guarding. Improves vertebral segmental function, reduces referred pain from lumbar dysfunction, and facilitates reciprocal inhibition of psoas muscle tension.

Region

Hip joint and anterior hip capsule

Technique

MET

Rationale

Muscle energy techniques applied to hip flexors using post-isometric relaxation principles effectively lengthen shortened psoas muscle. Patient-generated gentle contraction followed by passive stretching leverages neurophysiological relaxation response, improving hip extension range and reducing muscle hypertonicity.

Region

Pelvic girdle and sacroiliac joints

Technique

Functional

Rationale

Functional technique addresses pelvic asymmetry and sacroiliac joint dysfunction that perpetuates psoas strain through altered biomechanics. Restores neutral pelvic position, reduces compensatory psoas activation, and improves lumbopelvic stability.

Region

Lower thoracic and lumbar spine

Technique

HVLA

Rationale

High-velocity low-amplitude thrust to thoracolumbar or lumbosacral segments may be appropriate in chronic cases with restricted segmental mobility. Restores segmental freedom, reduces centralised referral patterns, and facilitates proprioceptive reset. Contraindicated in acute inflammation or neurological compromise.

Region

Abdominal contents and mesenteric structures

Technique

Lymphatic

Rationale

Gentle abdominal lymphatic technique promotes drainage of inflammatory exudate from strained psoas muscle, reduces local swelling, and enhances tissue healing. Facilitates visceral mobility and reduces referred abdominal wall tension patterns associated with psoas dysfunction.

Add-On Approaches

Chinese Medicine

TCM addresses psoas strain as liver blood and kidney essence deficiency causing sinew malnourishment. Acupuncture points LV3 (Tai Chong), KI3 (Taixi), and local points ST30 (Qi Chong) are used to move liver qi, tonify kidney essence, and regulate hip flexor function. Moxibustion over lower dantian supports kidney qi. Herbal formulas like Du Zhong (Eucommia) and Xu Duan (Dipsacus) support tendon and ligament healing.

Chiropractic

Chiropractic addresses underlying spinal misalignment (subluxation) contributing to psoas dysfunction. Lumbar and sacroiliac adjustments restore proper segmental function and reduce reflex psoas muscle guarding. Joint mobilisation combined with ergonomic advice for desk workers addresses postural aetiologies.

Physiotherapy

Physiotherapy emphasises active range of motion, progressive strengthening of hip extensors and abductors, core stability training (transversus abdominis and multifidus), and proprioceptive re-education. Targeted stretching of psoas and rectus femoris, postural re-education, and ergonomic workplace modification address causative factors. Graded return-to-sport protocols prevent re-injury in athletes.

Remedial Massage

Deep tissue and remedial massage techniques address myofascial trigger points within the psoas muscle, reduce associated tension in rectus abdominis and surrounding tissues, and improve muscle extensibility. Techniques work synergistically with osteopathic treatment to reduce protective muscle guarding and facilitate tissue healing through improved local circulation.

Rehabilitation Exercises

Supine Hip Flexor Stretch (Pectineus and Psoas)

StretchingBeginner

Kneeling Hip Flexor Lunge Stretch

StretchingBeginner

Supine Figure-Four Stretch (Piriformis and Hip External Rotators)

StretchingBeginner

Supine Hip Flexion and Extension (Pendulum Motions)

Range of MotionBeginner

Glute Bridge (Hip Extensor Activation)

StrengtheningBeginner

Quadruped Hip Extension (Glute Activation)

StrengtheningBeginner

Supine Pelvic Tilt and Transversus Abdominis Engagement

PosturalBeginner

Sidelying Hip Abduction (Hip Stabilisers)

StrengtheningIntermediate

Single-Leg Glute Bridge (Unilateral Hip Stability)

StrengtheningIntermediate

Standing Hip Flexor Stretch with Contralateral Lean

BalanceIntermediate

Prone Hip Extension with Knee Bent (Isolated Psoas Loading)

StrengtheningIntermediate

Plank Hold with Hip Neutral Positioning (Core Stability)

PosturalAdvanced

Referral Criteria

  • •Inability to bear weight or walk suggesting complete muscle rupture or severe acute strain requiring imaging (MRI/ultrasound)
  • •Unilateral leg swelling with warmth and possible calf symptoms suggesting deep vein thrombosis requiring urgent vascular assessment
  • •Fever, severe systemic illness, or signs of infection suggesting psoas abscess requiring medical imaging and possible antibiotics
  • •Acute cauda equina syndrome presentation (bilateral leg pain, bowel/bladder dysfunction, saddle anaesthesia) requiring immediate neurosurgical evaluation
  • •Persistent severe night pain unresponsive to conservative treatment suggesting malignancy or serious pathology requiring imaging and oncology referral
  • •Neurological signs (progressive weakness, sensory loss, reflex changes) suggesting nerve compression requiring neurology or neurosurgery assessment
  • •No improvement after 6-8 weeks of conservative treatment requiring advanced imaging (MRI) to exclude structural pathology or surgical consultation
  • •Concurrent abdominal symptoms (nausea, vomiting, altered bowel function) suggesting possible visceral involvement requiring medical evaluation
  • •History of significant trauma with severe initial pain and imaging findings of complete muscle rupture potentially requiring surgical intervention