What Is Runner's Knee?
Runner's knee — clinically known as patellofemoral pain syndrome (PFPS) — refers to pain around or behind the kneecap (patella). It's one of the most frequently diagnosed conditions in runners, particularly those who have recently increased their training volume or intensity.
Despite the name, runner's knee isn't exclusive to runners. But the repetitive loading involved in running makes it especially common in this population.
Common Causes and Contributing Factors
Runner's knee rarely has a single cause. It's typically the result of several overlapping factors:
- Rapid mileage increases: Adding too much volume too quickly overloads the knee joint before it can adapt.
- Weak glutes and hips: When the glutes and hip abductors are weak, the femur (thigh bone) rotates inward, increasing stress on the patella.
- Poor running form: Overstriding, excessive forward lean, or knee valgus (knees caving inward) can all contribute.
- Worn-out shoes: Shoes that no longer provide adequate cushioning or support change the load distribution on your joints.
- Running on hard surfaces: Consistently running on concrete amplifies impact forces compared to softer surfaces like trails or tracks.
- Tight IT band or quad muscles: Tightness in surrounding muscles can pull the patella out of its natural tracking path.
Recognising the Symptoms
Key signs of runner's knee include:
- A dull ache or sharp pain around or behind the kneecap
- Pain that worsens going downstairs, downhill, or after sitting for a long time
- A grinding or clicking sensation in the knee
- Swelling around the kneecap (in more acute cases)
Treatment: What to Do When It Strikes
If you suspect runner's knee, the first step is to reduce or temporarily stop running to allow inflammation to settle. Then:
- Ice and compression: Apply ice for 15–20 minutes after activity. A compression sleeve can help manage swelling.
- Reduce load: Swap high-impact sessions for low-impact cross-training (cycling or swimming) to maintain fitness without aggravating the knee.
- Address the root cause: Work with a physiotherapist to identify whether weakness, tightness, or form issues are the primary driver.
- Gradual return to running: Ease back in with shorter, flatter runs on softer surfaces before rebuilding volume.
Prevention: The Strength Work That Protects Your Knees
The most effective long-term prevention strategy is building strength in the muscles that support the knee. Incorporate these exercises 2–3 times per week:
- Clamshells: Targets hip abductors and external rotators
- Single-leg squats (pistol progressions): Builds quad and glute strength with balance challenge
- Glute bridges and single-leg glute bridges: Activates and strengthens the posterior chain
- Step-ups: Functional knee strengthening
- Side-lying leg raises: Hip abductor endurance
When to See a Professional
If pain persists beyond a few weeks despite rest and strengthening, or if you notice significant swelling, instability, or pain at rest, seek assessment from a physiotherapist or sports medicine professional. Don't push through persistent knee pain — early intervention almost always means a faster return to running.
The Bottom Line
Runner's knee is common but not inevitable. Respect the warning signs early, build strength in your hips and glutes, progress your training gradually, and you'll give your knees the best possible chance of staying healthy mile after mile.