Knee pain when running: common causes and when to see a physio
Knee pain when running is one of the more frequent reasons active people book a physiotherapy appointment. It rarely arrives out of nowhere. Usually there's a change somewhere in the background, a jump in weekly kilometres, a new hill route, a return to running after a few quiet months, and the knee starts complaining a few days later.
The knee itself isn't always the origin of the problem. Load tolerance at the hip, ankle and foot all feed into how the knee copes with repeated impact. That's part of why two runners with similar symptoms can need quite different management, and why our earlier piece on how a physiotherapist can help with running injuries starts with training history rather than the sore joint.
Individual presentations vary considerably, and for some people the picture is more complicated than any article can cover. This information doesn't replace an in-person assessment.
How common is knee pain in runners?
Knee complaints make up a large share of running-related injuries. A systematic review of running-related musculoskeletal injuries published in the Journal of Sport and Health Science reported patellofemoral pain at 6.3% of injury incidence and 16.7% of injury prevalence among runners. Looking more broadly, a 2018 systematic review and meta-analysis in PLOS ONE estimated annual prevalence of patellofemoral pain in the general population at 22.7%.
The pattern is well described enough that a structured assessment may narrow things down without imaging in the first instance. A knee that keeps flaring still needs looking at, though.
Common causes of runners knee
Runners knee is a loose umbrella term rather than a single diagnosis. Several distinct presentations sit underneath it, and where the pain sits is the quickest way to tell them apart. Most of them fall within the broader category of sports and overuse injuries.
Patellofemoral pain, felt at the front of the knee
Pain sits around or behind the kneecap. Healthdirect describes this as pain where the kneecap runs over the end of the thigh bone, and runners often report an ache that builds during a run rather than a sharp catch. Stairs, squatting, and long periods sitting with the knee bent tend to reproduce it.
Load management, hip and quadriceps strengthening and a gradual return to running are commonly used in physiotherapy management of patellofemoral pain. We've written separately about physiotherapy exercises for knee pain, though individual responses to treatment vary and physiotherapy isn't suitable for every presentation.
Iliotibial band syndrome, felt on the outside of the knee
The pain is sharper and more localised, sitting on the outer aspect of the knee. It often appears at a fairly predictable point in a run, then eases with rest, then returns at roughly the same distance next time. Downhill running and cambered footpaths are frequent aggravators. Some people notice it on one side only. For others it settles with load changes alone.
Patellar tendinopathy, felt just below the kneecap
Here the tender spot is at the lower pole of the kneecap or the tendon beneath it. Jumping, hill sprints and speed work load this tissue heavily. Tendon presentations often warm up during activity and feel worse the following morning, which can make them easy to underestimate early on. Management usually centres on graded loading rather than rest, sometimes alongside soft tissue massage or joint mobilisation as adjuncts.
Other possibilities
Fat pad irritation, meniscal issues and early osteoarthritic change can all present as knee pain after running. So can referred pain from the hip or lumbar spine, which is a distinction we cover in more detail in our article on telling sciatica from hamstring pain. A straightforward muscle strain around the thigh or calf sometimes shows up as knee-area soreness too. Age, training history and the way symptoms behave over a week all help distinguish between them.
What tends to bring it on
Most running knee complaints trace back to a mismatch between what the tissue was ready for and what it was asked to do.
A rapid increase in weekly distance, session frequency or intensity, often in the four to six weeks before symptoms appear.
A change in terrain or surface, such as adding hills, trail sections or repeated downhill running.
Returning to running after illness, injury or an extended break, at close to the previous training volume.
Reduced strength or endurance through the hip and calf, which alters how force is absorbed at the knee. Restricted hamstring flexibility can play a part for some runners.
Footwear that has been changed abruptly, or shoes well past their usual mileage.
Marathon and half-marathon preparation is a common backdrop for all of this. Adelaide runners building towards spring events often report symptoms starting during the heaviest block of their programme.
When to see a physio about knee pain when running
Short-lived soreness after an unusually hard session is a normal training response. Pain that keeps building, or keeps returning at the same point in a run, suggests the load is outrunning what the tissue can handle. Worth booking an assessment if any of these apply to you.
Pain has lasted longer than two weeks despite reducing your running.
You've altered your gait, shortened your stride or started limping to get through a run.
Symptoms return at the same distance every time, suggesting a load-related pattern rather than a one-off.
Swelling appears after running, or the knee feels stiff first thing in the morning.
The same knee has troubled you before and the episodes are becoming more frequent.
Some symptoms warrant urgent medical review rather than a physiotherapy appointment. Healthdirect advises seeing a doctor urgently if you have a fever alongside a red, swollen knee, or if you can't put any weight on the leg. A knee that locks or gives way also needs prompt medical assessment. Physiotherapy is not suitable for all presentations.
What an assessment usually involves
A physiotherapy assessment for running knee pain generally starts with your training history rather than your knee. Weekly volume, recent changes, footwear, event goals and previous injuries all shape the picture.
From there, a physiotherapist typically looks at knee range of movement, strength through the hip, quadriceps and calf, single leg control, and how you tolerate specific loading tests. Some clinicians also observe running mechanics. That mapping shows which movements reproduce your symptoms and which don't. Your physiotherapist may then use that picture to shape a management plan, often built around a prescribed exercise program, though what's appropriate differs from person to person.
Imaging isn't routinely indicated for most running knee presentations. RACGP clinical guidance reserves knee MRI for cases where there's real doubt about the diagnosis and where confirming it would change management. Where osteoarthritis is suspected, the RACGP guideline for the management of knee and hip osteoarthritis sets out the recommended non-surgical approach. Your physiotherapist or GP can advise on when imaging may be appropriate in your circumstances.
Can you keep running with knee pain?
Sometimes, in a modified form. Complete rest isn't automatically the answer for load-related knee pain, and prolonged inactivity carries its own downsides for tendon and muscle capacity. Many programmes involve adjusting distance, pace, surface and frequency rather than stopping outright.
That decision depends on the diagnosis and how your symptoms behave during and after a run. A sports physiotherapist can talk through what modification might look like for you, though individual responses to treatment vary and outcomes can't be predicted in advance.
Ducker Physio in Adelaide
Ducker Physio assesses and manages running and training-related complaints, including joint pain and post-surgical rehabilitation. Suitability is assessed case by case, and physiotherapy isn't suitable for all presentations.
Magill clinic, 465/467 The Parade, Magill SA 5072. Salisbury clinic, 9 Mary Street, Salisbury SA 5108. Initial 20-minute assessments, after-hours sessions and same-day appointments are sometimes available. You can make a booking online or send an enquiry.
Frequently Asked Questions
Why do my knees hurt when I run?
Most often it relates to load. The tissues around the knee tolerate a certain amount of repeated impact, and symptoms tend to appear when that threshold is exceeded, usually after a change in training. Structure matters too, but training history is generally the first thing a physiotherapist will ask about.
Can I keep running with knee pain?
It depends on the cause and the severity. Mild, settling symptoms may allow modified running to continue for some people. Pain that alters your gait, worsens session to session or persists into the following day suggests a review is sensible before you push on.
What causes pain at the front of the knee when running?
Patellofemoral pain is the most commonly described cause of anterior knee pain in runners. It's typically an ache rather than a sharp pain, and it's often reproduced by stairs, hills and prolonged sitting. Patellar tendinopathy can also present at the front, though the tender area is usually lower and more precisely located.
What causes pain on the outside of the knee when running?
Iliotibial band syndrome accounts for a large proportion of lateral knee pain in runners. The classic report is pain that appears at a consistent distance into a run, settles with rest, then reappears at a similar point next time. Downhill sections often make it worse.
Do I need a scan for runners knee?
Usually not. Imaging is generally reserved for presentations where the result would change what happens next, or where concerning features are present. A clinical assessment is normally the appropriate first step, and you'll find more on what to expect on our FAQ page.
How long does knee pain from running take to settle?
Timeframes vary considerably between individuals and depend on the diagnosis, how long symptoms have been present, and training demands. For some people the pattern settles quickly, for others it doesn't. No timeframe can be promised in advance.
Where can I see a physio for running knee pain in Adelaide?
Ducker Physio has clinics at Magill and Salisbury, and a physiotherapy service at Calvary Central Districts Hospital in Elizabeth Vale. No GP referral is required to book an appointment for a running injury physio in Adelaide.
Sources
General information only. Individual symptoms and appropriate treatment vary. If you experience red flag symptoms including severe weakness, bladder or bowel changes, or saddle area numbness, seek emergency medical attention.