What Is Femoroacetabular Impingement?
Femoroacetabular impingement (FAI) is a condition where the ball of the hip joint doesn't fit perfectly into the socket. Over time, this imperfect fit causes the cartilage and ligaments around the hip to wear and become painful.
FAI is increasingly diagnosed in Ireland, particularly among GAA players, hurdlers, and athletes in sports demanding deep hip flexion and rotation. But it also affects people who've never played sport — the hip's architecture can create impingement in everyday movements like sitting, standing, and walking.
The Hip Ligament Architecture
The hip joint is reinforced by three major ligaments:
- Iliofemoral ligament: The strongest ligament in the body, it reinforces the front of the hip and limits hyperextension
- Pubofemoral ligament: Limits excessive abduction and extension
- Ischiofemoral ligament: Reinforces the back of the hip and limits internal rotation
When FAI is present, the ball and socket don't glide smoothly. These ligaments are placed under asymmetric tension, and the labrum — the cartilage ring around the socket — can become pinched and damaged.
Why FAI Causes Pain
The impingement creates pain through several mechanisms:
- Mechanical pinching: The ball bumps against the socket's rim during certain movements, directly irritating the labrum and ligaments
- Ligament tension asymmetry: The hip ligaments tighten unevenly to compensate for the imperfect fit, creating chronic strain
- Muscle compensation: The hip muscles work harder to stabilise the joint, becoming tight and painful
- Nervous system sensitivity: Persistent irritation sensitises the nerves around the hip, amplifying pain signals
The Metacognitive Approach
Step 1: Identify Your Impingement Pattern
FAI pain follows patterns. Which movements cause the pinch?
- Deep squatting: Usually indicates cam impingement (the ball has extra bone)
- Sitting cross-legged: Often relates to pincer impingement (the socket covers too much)
- Internal rotation: Both types can cause pain here
This awareness helps you understand which movements to modify and which to approach gradually.
Step 2: Feel the Ligament Chain
Your hip doesn't work in isolation. It's part of a chain:
- Pelvic ligaments: The sacroiliac joints and pubic symphysis connect the pelvis. If these are tight, the hip compensates.
- Knee ligaments: If the knee is unstable, the hip muscles work overtime to stabilise the leg.
- Spinal ligaments: Lumbar stiffness shifts load to the hip during movement.
Can you feel where the tension begins? Is it in the hip itself, or is the hip compensating for restriction elsewhere?
Step 3: Modify and Rebuild
FAI doesn't always require surgery. Many people manage it successfully with:
- Movement modification: Avoiding the specific angles that cause impingement
- Hip muscle strengthening: Strong glutes and hip rotators share the load with the ligaments
- Mobility in safe ranges: Moving the hip through pain-free ranges maintains joint health
- Core and pelvic stability: A stable pelvis reduces the hip's compensatory workload
The Irish Sporting Context
- GAA: Kicking, sprinting, and cutting load the hip in rotation and flexion
- Hurling: The swing requires deep hip rotation on the plant leg
- Rugby: Sprinting and tackling create high-impact hip loads
- Irish dancing: Deep hip flexion and rotation demand exceptional hip mechanics
- Distance running: Ireland's growing running community sees hip pain from repetitive load
Action Steps
- Map your pain: For one week, note which movements cause hip pinch. Deep sitting? Walking uphill? Standing from a chair? This reveals your impingement pattern.
- Strengthen the glutes: The gluteal muscles are the hip's primary stabilisers. Bridges, clams, and single-leg work build capacity.
- Mobilise the pelvis: Gentle pelvic tilts and sacroiliac mobilisations reduce compensatory hip strain.
- Avoid the pinch: If deep squats hurt, modify the depth. If cross-legged sitting hurts, sit differently. This isn't avoidance — it's intelligent management.
- Feel the chain: When walking, can you feel the force travel from your foot through your hip to your spine? Smooth force transmission means less hip strain.
The Mindset Shift
FAI can feel like a structural sentence — if the bone shape is wrong, what can you do? But here's the truth: many people with FAI on imaging have no pain at all. The bone shape creates a vulnerability, not a destiny.
The pain comes from how your body has adapted to the architecture. The ligaments have tightened asymmetrically. The muscles have compensated. The nervous system has become sensitised. All of these can change.
By approaching your hip with awareness — feeling the pinch, understanding the chain, strengthening the stabilisers — you begin to change the relationship between the bone shape and the pain. Your hip can find a new way to move that doesn't impinge, doesn't strain, doesn't hurt.
The path isn't quick. But it's real. Every aware step, every strengthened glute, every modified movement is a step toward a hip that works with you, not against you.
PAIN APPLICATION — WHAT WOULD WE MEASURE?
This is a measurement example, not a case study. No individual's recorded data appears here.
For a loaded hip-flexion task, an assessment may record:
- the reported pain score
- Sensor Sling pressure where relevant
- pressure distribution
- angle/orientation where supported
- timing
- sequence
- repeatability
- loading
- movement response
The process is the same as for any I AM 900 assessment:
ESTABLISH BASELINE → MEASURE → CHANGE INPUT → RETEST → COMPARE
Sensor Sling measurement does not diagnose femoroacetabular impingement, labral tears or any specific hip pathology — and pressure measurements do not identify which structure causes pain.
Pressure Distribution and Pain: What Measurement Can — and Cannot — Tell Us sets out how the comparison works.
