Hip Flexor Strain

Lower Limb

Overview

Hip flexor strain is an acute or chronic injury to the iliopsoas complex, rectus femoris, or sartorius muscles, commonly occurring from sudden acceleration, kicking, or prolonged flexion activities. This condition presents with anterior hip or groin pain and restricted hip extension, affecting athletes and sedentary individuals alike. Early intervention with osteopathic treatment and targeted rehabilitation significantly improves outcomes and prevents chronic dysfunction.

Pathophysiology

Hip flexor strain results from excessive tension, overstretching, or microtrauma to the muscles responsible for hip flexion and lumbar stabilization. The iliopsoas (iliacus and psoas major) is most commonly affected, particularly at its insertion on the lesser trochanter. Repetitive shortening from prolonged sitting, sudden eccentric loading during sprinting or kicking, or direct trauma causes inflammation, muscle fiber disruption, and subsequent weakness. Secondary effects include altered lumbopelvic mechanics, compensation patterns in the kinetic chain, and potential development of myofascial trigger points. Chronic strains may develop adhesions restricting normal tissue mobility.

Patient Education

Hip flexor strengthening and regular stretching following proper progression are essential; avoid aggressive stretching in acute phases and gradually restore full active range of motion to prevent re-injury.

Typical Presentation

Site

Anterior hip, groin region, or lower abdomen; pain may refer to lower lumbar spine or medial thigh

Quality

Sharp, stabbing, or aching pain; may describe tightness or cramping sensation

Intensity

Mild to moderate (3-7/10) in chronic cases; severe (7-9/10) in acute strain with significant muscle disruption

Aggravating

Hip flexion activities (stair climbing, sprinting, kicking), sitting for prolonged periods, standing with hip hyperextension, active straight leg raise, resisted knee flexion in supine

Relieving

Rest, ice application, recumbent positioning, gentle stretching in pain-free range, anti-inflammatory medication

Associated

Reduced hip extension range of motion, weakness in hip flexion strength testing, possible palpable muscle tightness or spasm, compensatory lower back pain, antalgic gait pattern, tightness in hip adductors and rectus femoris

Orthopaedic Tests

Test descriptions are written with AI assistance from standard clinical texts. Where a test lists Sources, its description has been checked against them; those sources are independent and do not endorse OsteoKit. Accuracy figures and grades (A–D) appear only when checked against the published study; tests without one are marked “No accuracy study”.

Further reading: full test procedures are described in standard clinical examination texts, e.g. Magee & Manske, Orthopedic Physical Assessment (7th ed.), and Cook & Hegedus, Orthopedic Physical Examination Tests: An Evidence-Based Approach (2nd ed.).

Grade B
A+ABCDGood clinical value: meaningfully changes the diagnosis in one direction (LR 5–10 or 0.1–0.2)
best for ruling OUT (screening).

Palpation for Muscle Tenderness

Procedure

Patient supine. Palpate the proximal rectus femoris just below the front of the hip (anterior inferior iliac spine), the sartorius just below the anterior superior iliac spine, and the iliopsoas just below the inguinal ligament, lateral to the femoral artery pulse. Compare with the other side.

Positive Finding

Tenderness that reproduces the patient's own pain, in a specific muscle.

Sensitivity / Specificity

89% (18 athletes with a hip flexor injury)/78% (63 injured athletes without one)

Reference: Serner A, Weir A, Tol JL, Thorborg K, Roemer F, Guermazi A, et al. Can standardised clinical examination of athletes with acute groin injuries predict the presence and location of MRI findings?. Br J Sports Med. 2016;50(24):1541-1547.

Interpretation

No tenderness makes a hip flexor injury on MRI unlikely. Tenderness at a bony point (anterior iliac spines) in an adolescent may be an apophyseal avulsion and needs an X-ray. From one study of 81 male athletes seen within 7 days of an acute groin injury, with MRI as the reference (Serner 2016). 18 had a hip flexor injury on MRI (rectus femoris, iliopsoas or sartorius); the comparison group was the 63 athletes with another groin injury or a normal MRI. The authors found hip flexor tests poor at predicting which muscle was injured, and suggested MRI when the exact location matters. Figures apply to acute injuries only.

Sources

Grade C
A+ABCDModest value: a small but usable shift in probability (LR 2–5 or 0.2–0.5)
modest, supportive value.

Resisted Hip Flexion Test

Procedure

Patient supine with the hip and knee bent to 90°. Ask the patient to pull the knee towards the chest against your resistance on the thigh. Repeat with the leg straight, lifting against your hand above the knee.

Positive Finding

Reproduction of the patient's own pain in the front of the hip or groin, or weakness.

Sensitivity / Specificity

67% (18 athletes with a hip flexor injury)/79% (63 injured athletes without one)

Reference: Serner A, Weir A, Tol JL, Thorborg K, Roemer F, Guermazi A, et al. Can standardised clinical examination of athletes with acute groin injuries predict the presence and location of MRI findings?. Br J Sports Med. 2016;50(24):1541-1547.

Interpretation

Supports a hip flexor injury. It does not separate iliopsoas from rectus femoris; use the strength tests in different positions and palpation for that. From one study of 81 male athletes seen within 7 days of an acute groin injury, with MRI as the reference (Serner 2016). 18 had a hip flexor injury on MRI (rectus femoris, iliopsoas or sartorius); the comparison group was the 63 athletes with another groin injury or a normal MRI. The authors found hip flexor tests poor at predicting which muscle was injured, and suggested MRI when the exact location matters. Figures apply to acute injuries only. Figures are for resisted hip flexion with the hip and knee bent to 90°.

Sources

No accuracy study

Thomas Test

Procedure

Patient sits at the end of the plinth, then lies back hugging one knee to the chest to flatten the lower back. The other leg hangs down. Look at the hanging thigh and knee, and repeat on the other side.

Positive Finding

The hanging thigh rises above the plinth (hip flexor tightness), and/or the knee straightens (rectus femoris tightness). Pain in the front of the hip may also be reproduced.

Interpretation

Shows hip flexor length and whether the stretch reproduces pain. Pain with passive hip extension in this position supports a hip flexor injury; tightness alone is a common finding and does not diagnose a strain.

Sources

No accuracy study

Ely's Test (Prone Knee Bend)

Procedure

Patient prone. Hold the pelvis steady and bend the knee, bringing the heel towards the buttock. Compare with the other side.

Positive Finding

The hip on the same side lifts off the plinth (flexes), the heel cannot reach the buttock, or pain is felt in the front of the thigh.

Interpretation

Tests rectus femoris length and stretches the muscle. Pain in the upper front thigh supports a rectus femoris strain; hip tightness alone is common and not diagnostic.

Sources

No accuracy study

Iliopsoas Strength Test (Manual Muscle Testing)

Procedure

Patient sitting on the edge of the plinth. Ask the patient to lift the knee towards the ceiling (beyond 90° of hip flexion) and hold against your downward resistance above the knee. Compare with the other side.

Positive Finding

Pain in the groin or front of the hip, or weakness compared with the other side.

Interpretation

Holding hip flexion above 90° mainly loads iliopsoas, as rectus femoris is at a disadvantage in this position. Pain supports an iliopsoas injury.

Sources

No accuracy study

Rectus Femoris Strength Test

Procedure

Patient in the modified Thomas position (lying back hugging the other knee, tested leg hanging). Ask the patient to straighten the knee against your resistance at the shin.

Positive Finding

Pain in the upper front thigh, or weakness.

Interpretation

Loads rectus femoris across both hip and knee. Pain supports a rectus femoris injury. A palpable defect or large bruise below the front of the hip suggests a more severe tear or avulsion and needs imaging.

Sources

⚠ Red Flags

  • •Acute severe trauma with inability to bear weight or move hip (possible avulsion fracture)
  • •Signs of deep vein thrombosis (unilateral calf or thigh swelling, warmth, deep-vein tenderness). Homan's sign is unreliable (sensitivity roughly 10-54%, specificity roughly 39-89%) and must not be used to include or exclude DVT
  • •Severe systemic illness with fever and localized swelling (possible infection)
  • •Progressive neurological deficit or numbness in groin/genitals (possible nerve compression or cauda equina)
  • •History of cancer with unexplained groin mass or weight loss
  • •Signs of testicular or pelvic pathology requiring urological evaluation

⚡ Yellow Flags

  • •High kinesiophobia or fear of movement limiting rehabilitation engagement
  • •Catastrophizing about injury preventing return to sport or activity
  • •Poor adherence to previous treatment or rehabilitation programs
  • •Significant psychological stress or depression affecting pain perception
  • •Excessive anxiety about re-injury limiting functional restoration
  • •Secondary gain considerations (litigation, compensation claims)
  • •Unrealistic recovery timeline expectations

Osteopathic Techniques

No trials of osteopathic or manual techniques for hip flexor strain were found. For iliopsoas problems, a reference chapter puts stretching, strengthening and changes to training first.

Region

Iliopsoas, rectus femoris and sartorius

Technique

Soft tissue, hip and thighNo trials found

Rationale

Eases tension in the hip and thigh muscles. Not tested in trials for this condition.

How it's done & evidence

How it's done

Hands-on kneading, stretching and sustained pressure to the muscles around the hip and thigh: the hip flexors, adductors and hamstrings, and tensor fasciae latae with the iliotibial band.

Evidence in Hip Flexor Strain

Searched 24 Oct 2026: no trials of hip flexor soft tissue technique in hip flexor strain.

Sources

Region

Psoas and iliacus

Technique

Muscle energy, psoasNo trials found

Rationale

Low-force MET or counterstrain to ease a tight, tender psoas. Not tested in trials for this condition.

How it's done, cautions & evidence

How it's done

The hip is taken into extension to the barrier (prone, or supine with the leg off the table). The patient pulls the hip toward flexion for 3–5 seconds against equal resistance, relaxes, and the hip is taken further into extension. Repeat 3–5 times, then re-check.

Cautions

Do not use with a fracture in the area, an unstable pelvis or hip, recent surgery, or a patient who cannot contract on request or follow directions.

Evidence in Hip Flexor Strain

Searched 24 Oct 2026: no trials of psoas MET in hip flexor strain.

Region

Hip joint

Technique

Articulation, hipNo trials found

Rationale

Gentle, rhythmic movement of the hip joint within its range to ease stiffness. Not tested in trials for this condition.

How it's done, cautions & evidence

How it's done

Rhythmic, low-velocity passive movement of the hip joint within its range, with no thrust, usually with the patient supine. In hip osteoarthritis trials it was given as a course of about 9–10 sessions over 5–12 weeks.

Cautions

Side effects are usually mild and short-lived. In one hip osteoarthritis trial, 41% of the active group (manual therapy plus exercise) reported mild side effects, against 14% with sham.

Evidence in Hip Flexor Strain

Searched 24 Oct 2026: no trials of hip mobilisation in hip flexor strain.

Region

Lumbar paraspinals and gluteals

Technique

Soft tissue, lumbar and glutealNo trials found

Rationale

Eases tension in the lower back and gluteal muscles. Not tested in trials for this condition.

How it's done, cautions & evidence

How it's done

Hands-on soft-tissue work (kneading, stretching and sustained pressure) to the lumbar paraspinals, quadratus lumborum and gluteal muscles, usually prone or side-lying.

Cautions

Only minor side effects have been reported in trials.

Evidence in Hip Flexor Strain

Searched 24 Oct 2026: no trials of lumbar soft tissue technique in hip flexor strain.

Sources

Rehabilitation Exercises

Prone Hip Extension Stretch (Rectus Femoris and Iliopsoas)

StretchingBeginner

Modified Lunge Hip Flexor Stretch

StretchingBeginner

Supine Figure-Four Stretch (Hip External Rotators)

StretchingBeginner

Seated Hip Flexion with Knee Extension (Active Range)

Range of MotionBeginner

Supine Hip Flexion Isometric Hold

StrengtheningBeginner

Standing Hip Flexion March (Marching in Place)

StrengtheningIntermediate

Supine Single Leg Raise with Hip Flexion

StrengtheningIntermediate

Quadruped Hip Extension Rocking

PosturalBeginner

Dead Bug (Core Stability with Hip Flexor Control)

Core StrengtheningIntermediate

Single Leg Stance on Unstable Surface

BalanceIntermediate

Resistance Band Hip Flexion (Standing)

StrengtheningIntermediate

Modified Step-Ups with Controlled Hip Flexion

FunctionalAdvanced

Referral Criteria

  • •Acute severe strain with signs of muscle rupture or avulsion fracture; refer to orthopedic surgeon or emergency medicine
  • •Symptoms persisting beyond 6-8 weeks despite appropriate conservative treatment; refer to sports medicine specialist or orthopedic surgeon
  • •Progressive neurological symptoms including numbness, tingling, or weakness in groin or thigh; refer to neurologist or neurosurgeon
  • •Signs of deep vein thrombosis or circulatory compromise; refer to vascular surgeon or emergency department immediately
  • •Concurrent hip pain with imaging evidence of labral pathology, femoroacetabular impingement, or severe osteoarthritis; refer to orthopedic surgeon
  • •Groin pain with signs of genitourinary pathology, hernia, or lymphadenopathy; refer to general practitioner or urologist
  • •Inability to progress with rehabilitation or recurring re-injuries; refer to sports medicine specialist to investigate kinetic chain dysfunction
  • •Significant psychological barriers to recovery affecting compliance; refer to sports psychologist or counselor