🏃‍♂️ Understanding Runner’s Knee (Patellofemoral Pain): Causes, Management, and the Latest Physio Insights

What Is Runner’s Knee?

Runner’s knee — medically known as patellofemoral pain syndrome (PFPS) — is one of the most common causes of anterior knee pain in runners and active adults.

It describes irritation or overload around the kneecap (patella), where the joint between the patella and thigh bone (femur) becomes sensitive due to repetitive strain, poor movement patterns, or muscular imbalances.

Although its name suggests it only affects runners, it can also occur in cyclists, gym-goers, and anyone who performs repeated knee-bending activities such as squats, climbing stairs, or lunging.

Common Signs and Symptoms

• A dull ache around or behind the kneecap

• Pain aggravated by running, squatting, or prolonged sitting (“the movie theatre sign”)

• Clicking, grinding, or mild swelling

• Pain when descending stairs or downhill running

Symptoms often start gradually and can worsen if training loads increase too quickly — a common mistake during race season or post-injury return.

What Causes Runner’s Knee?

Recent research shows that patellofemoral pain is not caused by a single “faulty structure,” but rather a combination of biomechanical, strength, load and psychosocial factors.

1. Quadriceps and Glute Imbalances

The word imbalance is often used in place of weakness. Weakness in the quadriceps or gluteal muscles can lead to altered knee tracking, increasing patellofemoral joint stress. These muscle groups absorb high levels of force with each stride, so an underlying weakness often exposes a capacity issue. Weaker muscles cope less with the demand of running, and as training ramps up patellofemoral pain often rears it's ugly head.

2. Training Load Errors

A sudden increase in mileage, intensity, or hill running can overload the joint faster than tissues can adapt. It's important to think of is run as a quantifiable load and the inability to tolerate it is rarely obvious after a single run.

If a runner weighs 50kg and their weekly volume is 12km (approx 10k steps) and each step is approx 6-7 times body weight weekly volume on the patellofemoral joint is:

50kg x 6-7 = 300-350kg per stride

300-350 x 10,000 strides = weekly volume 3,000,000-3,500,000kg per week (1,500,000 - 1,750,000kg per leg)

Adding 5km, by introducing another run or extending your long run would add approx 4k steps which adds a further 600,000 - 700,000 kg per leg.

3. Reduced Shock Absorption

Poor calf strength or limited ankle mobility decreases the limb’s ability to dissipate force — sending more stress to the knee joint. This is one of the reasons that a hollistic Strength & Conditioning is crucial.

Stronger leg muscles will absorb and produce more force, but something that is very undervalued is the adaptation that strength training has on tendons. It stiffens them! In running stiff tendons = good news, because tendons act like springs! The stiffer the tendon the more elastic energy you produce, which increases running economy.

Modern Management: Evidence-Based Physiotherapy

Gone are the days of “just rest and stretch.”

Current management for runner’s knee focuses on load optimisation, strength training, and movement retraining.

1. Load Management (Don’t Just Stop Running)

Completely stopping all activity can cause deconditioning and delay recovery.

Instead, the goal is to adjust intensity, duration, and terrain while maintaining cardiovascular fitness through low-impact options such as cycling or pool running.

Physiotherapists now use pain monitoring models (stay below 3–4/10 pain) to guide safe training adjustments.

2. Targeted Strength & Conditioning

Progressive loading of the knee and hip muscles is central.

Key exercises include:

• Isometric knee extensions to control pain

• Split squats and step-downs to build load tolerance

• Hip abductor and gluteal strengthening

• Calf and hamstring work to improve energy absorption

At The Knee Physio, we use VALD force platform testing to quantify left–right strength asymmetry, squat symmetry, and jump performance — turning subjective “weakness” into measurable data that guides progression.

3. Movement Re-education

Video or force analysis can identify mechanical issues such as excessive hip drop or knee collapse during running or squatting.

Cueing strategies and strength correction help re-establish optimal knee alignment under load.

4. Education & Self-Management

Understanding that pain does not always equal damage is empowering.

Explaining the role of gradual loading, recovery, and long-term knee capacity helps runners stay consistent rather than fearful of movement.

5. Adjuncts

Taping, patellar straps, or short-term orthotics can provide temporary relief, but the long-term solution lies in capacity building, not bracing.

When to Seek Expert Help

If knee pain persists for more than a few weeks, limits your training, or causes difficulty in daily activities, a comprehensive physiotherapy assessment is essential.

At The Knee Physio in Bury St Edmunds, we specialise in data-led rehabilitation using VALD testing systems to detect strength asymmetries and track progress over time.

By combining physiotherapy principles with strength and conditioning expertise, we can design precise, evidence-based programs that restore knee function and prevent recurrence.

The Takeaway

Runner’s knee is rarely a simple “overuse injury” — it’s a sign that your training load, strength, and movement controlare slightly out of sync.

With modern physiotherapy approaches, AI-driven data analysis, and structured load progression, most runners can recover fully and return to pain-free training.

So if your knees ache after every run, don’t just push through it - address it early.

A professional screening could be the difference between weeks of frustration and a strong, confident return to the road or trail.