Hip impingement or femoroacetabular impingement (FAI) occurs when abnormal bone contact between the femoral head and hip socket creates friction during movement, and athletes often feel this most during running, squatting, and pivoting.
Unlike an acute injury, it typically develops as gradual groin pain that worsens with specific movements, and is often mistaken for a muscle strain before proper diagnosis.
The Role of Bone Shape in Hip Friction
In a normal hip, the femoral head glides smoothly within the socket through the full range of motion, but certain bone shapes can disrupt this and create abnormal contact.
- Cam morphology: A bony bump at the femoral head-neck junction that can jam against the socket rim during flexion and internal rotation, compressing the labrum
- Pincer morphology: Excess socket coverage that can crush the labrum against the femoral neck, with many athletes having both types combined
- Development: These variations often form during adolescent skeletal growth, particularly in athletes in high-impact sports, though the exact mechanisms are still being studied
How Running Can Trigger Hip Pain
Running involves repetitive hip flexion, and while this range alone rarely triggers impingement, cumulative loading across training distances may contribute over time. Uphill running and sprinting generally increase hip flexion and joint forces, which may bring athletes with cam morphology closer to the impingement zone. Fatigue can also alter running mechanics, increasing movements such as internal rotation and adduction that may provoke symptoms.
How Squatting Can Place Stress on the Joint
Squatting to parallel typically requires approximately 90 to 100 degrees of hip flexion, with deeper squats reaching 120 degrees or more, a range that can enter the impingement zone in athletes with FAI morphology. Loaded squats may further increase joint forces and mechanical stress on the hip.
- Knee position: Knees collapsing inward during a squat may increase cam lesion contact with the labrum
- Compensation patterns: Athletes may posteriorly tilt the pelvis to reach depth, which can shift stress to the lower back while still compressing the labrum
- Load and symptoms: Pain is often absent during bodyweight squats but may appear under load, sometimes with clicking or catching sensations
Why Pivoting and Rotating Cause Flare-Ups
Sports involving rapid direction changes, such as football, basketball, tennis, hockey, and martial arts, combine hip flexion with rotation in ways that can directly load the impingement lesion. Kicking movements can also place the hip at end-range flexion during the wind-up phase.
- Cutting movements: Deceleration and redirection phases can generate high joint compression, and athletes may unconsciously alter technique to avoid pain
- Kicking: May cause anterior labral compression in athletes with cam lesions, often felt as groin pain at the top of the kicking arc
Recognising the Symptom Pattern
Hip impingement in athletes produces a characteristic clinical picture. Primary symptoms include:
- Groin pain localised to the anterior hip crease, sometimes radiating to the inner thigh
- Activity-related symptoms that worsen during or after provocative movements and ease with rest
- Position-specific discomfort, particularly sitting in low chairs, getting in and out of cars, or during hip flexion stretches
- Stiffness after prolonged sitting or upon waking
- Mechanical symptoms such as clicking, catching, or locking sensations during certain movements
Pain typically develops gradually rather than from a single incident. Athletes often describe months of intermittent symptoms before seeking evaluation. Initial presentation may be dismissed as a groin strain or hip flexor issue, with temporary improvement from rest creating a cycle of activity-rest-activity.
The “C-sign” is commonly demonstrated by affected athletes: when asked to indicate pain location, they cup their hand in a C-shape around the anterior and lateral hip, reflecting the deep, ill-defined nature of the discomfort.
Diagnostic Assessment Process
Diagnosis typically combines clinical examination with imaging to confirm the structural findings behind a patient’s symptoms.
- FADIR test: The hip is passively flexed to 90 degrees, then adducted and internally rotated; pain reproduction suggests intra-articular pathology, though this test alone cannot distinguish impingement from other hip conditions
- FABER test: Assesses both hip and sacroiliac joint involvement; reduced range compared to the unaffected side, combined with groin pain, supports an FAI diagnosis
- Plain radiographs: Assess bone morphology using standardised measurements, including the alpha angle (commonly 55 to 60 degrees for cam morphology, though the exact threshold is debated) and lateral centre-edge angle and crossover sign for acetabular coverage
- MR arthrogram: MRI with intra-articular contrast provides detailed visualisation of labral tears, cartilage damage, and bone oedema, helping guide treatment decisions beyond what radiographs reveal
Conservative Management Approaches
Initial treatment focuses on activity modification, targeted rehabilitation, and symptom management. The goal is optimising hip function while reducing provocative loads.
Activity modification involves temporarily avoiding movements that reproduce symptoms. This doesn’t mean complete rest; rather, it typically involves substituting aggravating activities with hip-friendly alternatives. Reducing squat depth, avoiding uphill running, and modifying sport-specific techniques may allow continued training while symptoms settle.
Rehabilitation targets hip stability, mobility, and neuromuscular control. Strengthening the gluteal muscles, particularly gluteus medius and maximus, may improve dynamic hip stability and help reduce compensatory movement patterns. Core stability work addresses trunk control during athletic movements.
Manual therapy techniques including joint mobilisation and soft tissue work address secondary muscle tightness that develops around an impinging hip. Hip flexor and adductor tightness commonly accompany FAI and may perpetuate symptoms.
Anti-inflammatory interventions including NSAIDs and corticosteroid injections may provide symptomatic relief but do not alter the underlying structural problem. Injections can also serve diagnostic purposes, since pain relief following an intra-articular injection may help confirm the hip joint as the pain source.
Surgical Considerations
When conservative management does not provide adequate function for athletic demands, surgical intervention addresses the bone morphology directly. Hip arthroscopy is a common approach for FAI cases, allowing bone reshaping and labral treatment through small incisions.
Femoral osteoplasty shaves the cam lesion, aiming to restore normal head-neck contour. Acetabuloplasty trims pincer overcoverage. Labral tears undergo either repair or reconstruction depending on tissue quality. Damaged cartilage may be addressed through debridement or microfracture techniques.
Post-operative rehabilitation spans several months, with return to sport typically occurring between 6-12 months depending on the procedure performed and sport demands. The phased rehabilitation progresses through range of motion restoration, strength rebuilding, sport-specific conditioning, and graduated return to play.
Not all structural impingement requires surgery. Many athletes with radiographic evidence of FAI morphology remain asymptomatic or successfully manage symptoms through conservative means. Surgical decisions weigh symptom severity, functional limitations, imaging findings, and athletic goals.
⚠️ Important Note
Continuing high-level sport with untreated symptomatic FAI risks progressive labral damage and cartilage wear. Early evaluation allows for informed decisions about activity modification or intervention before secondary joint damage develops.
Movement Modifications for Symptomatic Athletes
Athletes managing hip impingement can implement specific technique adjustments:
For runners: Reduce training volume and avoid aggressive hill sessions during symptomatic periods. Transition gradually to flat surfaces. Address cadence and stride length; shorter, quicker strides may reduce peak hip flexion demands.
For squatters: Limit depth to pain-free range. Experiment with stance width and toe angle to find positions that reduce impingement loading. Box squats provide a depth-limiting tool. Consider temporarily substituting hip-dominant exercises like Romanian deadlifts or hip thrusts.
For pivoting athletes: Rehearse modified cutting patterns with wider turns. Strengthen hip abductors to improve stance-leg stability during direction changes. Work with coaching staff on sport-specific technique adjustments.
When to Seek Professional Help
- Groin or anterior hip pain persisting beyond several weeks despite rest
- Pain that limits training performance or requires regular analgesic use
- Clicking, catching, or locking sensations during hip movement
- Progressive loss of hip range of motion
- Symptoms recurring with activity after apparent resolution
- Night pain or pain at rest suggesting advancing pathology
Commonly Asked Questions
Can hip impingement heal on its own?
The bone morphology causing impingement does not change spontaneously. However, symptoms may resolve through activity modification and rehabilitation that reduces provocative loading. Many athletes successfully manage their condition without surgery by adjusting training patterns and maintaining hip strength and mobility.
Does continuing to train worsen the condition?
Training through symptomatic impingement risks progressive labral and cartilage damage. Modified training that avoids provocative movements may be sustainable, but pushing through significant pain likely accelerates joint wear. It is important to distinguish between mild activity-related symptoms and progressive joint damage.
At what age does hip impingement typically develop?
The bony abnormalities often form during adolescent skeletal development, particularly in athletes training intensively before growth plate closure. However, symptoms may not appear until adulthood when cumulative joint stress reaches a threshold. Presentation commonly occurs in the twenties and thirties among active individuals.
Can I prevent hip impingement?
Since the structural predisposition likely develops during skeletal growth, prevention of the bone morphology itself may not be possible. However, optimising hip strength, mobility, and movement patterns may reduce symptom development in those with underlying structural changes. Avoiding excessive loading during adolescent growth periods warrants consideration.
How do I know if my hip pain is impingement versus a muscle strain?
Muscle strains typically follow a specific incident, localise to muscle tissue, and improve predictably over days to weeks. Impingement pain centres in the anterior groin crease, worsens with specific positions (deep hip flexion, prolonged sitting), may be accompanied by clicking or catching, and follows a more chronic pattern. Clinical examination and imaging can help distinguish between these conditions, though a combination of history, exam findings, and imaging is usually needed rather than any single test alone.
Next Steps
Symptomatic FAI does not resolve through rest alone; managing the condition requires load management or structural evaluation. Athletes experiencing anterior groin pain during running, squatting, or pivoting can benefit from a clinical assessment to confirm FAI, evaluate associated labral health, and determine whether conservative rehabilitation or surgical options are appropriate before secondary joint wear develops.
If you are experiencing groin pain or mechanical clicking during running, squatting, or pivoting activities that impact your training performance, a consultation with an orthopaedic surgeon can help evaluate your hip joint and outline suitable treatment options.
