You run, and somewhere into the run the knee starts to hurt, at the front, on the outside or just below the kneecap, and the question is whether to push through, stop or change something. Knee pain when running is the most common running injury, and in most runners the cause is a training error rather than a damaged knee: distance or intensity raised faster than the tissues adapted, with hip weakness and a long, slow stride adding load to the kneecap and the outer knee on every step.
Three diagnoses account for most of it, and each has a location and a pattern you can recognise on the next run. This guide sets out the causes of knee pain when running by where it hurts, the training errors behind them, how to check which one you have, the training changes that reduce the load, how each is treated and when running knee pain needs to be assessed.
Key takeaways
- Knee pain when running is most often patellofemoral pain at the front of the knee, iliotibial band syndrome on the outer knee or patellar tendinopathy just below the kneecap, and the location separates them.
- A rise in weekly distance or intensity of more than about 10 per cent, hills, speed work and a return after a break are the training errors behind most running knee pain.
- Raising cadence by 5 to 10 per cent, shortening the stride and strengthening the hip abductors reduce the load on the kneecap and the outer knee without stopping running.
- Running through pain that rises above a mild level, or that lasts into the next morning, delays recovery; running at a level that produces mild symptoms only is part of the treatment.
- Knee pain when running settles in 6 to 12 weeks for most runners with load management and progressive strengthening, and a scan is rarely needed.
What causes knee pain when running?
Knee pain when running comes from the kneecap joint, the iliotibial band or the patellar tendon in most runners, and where the pain sits tells you which. Each structure is loaded on every stride, and each fails in its own way when the load rises faster than it can adapt.
| Where it hurts when running | Most likely cause | Pattern on the run |
| Front of the knee, around or behind the kneecap | Patellofemoral pain | Builds gradually, worse downhill and on stairs afterwards, aches after sitting |
| Outer side of the knee | Iliotibial band syndrome | Sharp or burning, starts at a predictable distance, worse downhill, stops soon after you stop |
| Just below the kneecap, on the tendon | Patellar tendinopathy | Worse at the start of a run, eases as you warm up, returns after, tender to press |
| Inner knee, 2 to 5 cm below the joint line | Pes anserine bursitis | Aches on hills and after longer runs, tender spot on the shin bone |
| Inner or outer joint line, with clicking | Meniscal irritation | Pain in deep bend and on turning, rather than on the stride itself |
| Whole knee, stiff next morning, over 45 | Early knee osteoarthritis | Aches after the run more than during it, stiff under 30 minutes in the morning |
The common thread. Each of the first three is a load problem. The kneecap joint takes several times body weight on each landing, the iliotibial band tightens over the outer knee at about 30 degrees of bend, and the patellar tendon stores and releases energy on every stride. A runner whose hips are weak and whose stride is long lands with the knee more bent and drifting inwards, which raises the load on all three. Our knee pain causes and treatment guide covers each diagnosis in the table.
Which training errors cause knee pain when running?
A rise in weekly distance or intensity of more than about 10 per cent, a block of hills or speed work, a return to running after a break, and new shoes or a new surface are the training errors behind most knee pain when running. The knee rarely fails on a steady programme.
Too much, too soon. Tissue adapts to load over weeks. Distance added faster than that, or a long run that is a large share of the week’s total, loads the kneecap and tendons past their current tolerance.
Hills and speed. Downhill running raises the load on the kneecap and the iliotibial band; speed work raises the load on the patellar tendon. A week that adds both is a common start point.
The return. Runners coming back after illness, injury or a winter off return at the distance they remember rather than the distance their tissues now tolerate.
Shoes and surface. A change in shoe drop or cushioning and a move from treadmill to road or trail change where the load lands. The change itself is the problem more than the shoe.
How do you work out which cause you have?
The location, the point in the run when the pain starts, and what happens after you stop separate the three common causes. Note all three on your next easy run.
Location. Place a finger on the worst spot after the run. Under or around the kneecap is patellofemoral. On the outer bony knob is iliotibial band. On the tendon just below the kneecap is patellar tendinopathy.
Timing. Pain at the start that eases as you warm up is the tendon. Pain that starts at the same distance each run and builds is the iliotibial band. Pain that builds gradually and is worse on the stairs afterwards is the kneecap.
After stopping. Iliotibial band pain fades within minutes. Kneecap pain lingers and returns on sitting. Tendon pain is worst the next morning. Our patellofemoral pain symptoms and self-test guide adds a self-test for the most common of the three.
The single-leg squat. Stand on the painful leg in front of a mirror and squat a quarter of the way down. A knee that drifts inwards and a hip that drops show the hip weakness that drives both kneecap and outer knee pain in runners.
Which training changes reduce knee pain when running?
Raising cadence by 5 to 10 per cent, shortening the stride, cutting the weekly load to the level that produces mild symptoms only, and avoiding downhill for two to three weeks reduce knee load enough for most runners to keep running while the knee recovers.
Cadence. Count your steps for one minute at easy pace, then aim for 5 to 10 per cent more steps at the same pace. A quicker, shorter stride lands the foot closer under the body with the knee less bent, which lowers the load on the kneecap and the outer knee on every step. A metronome app or a playlist at the target beat holds the rhythm.
Load. Reduce weekly distance to a level where pain during the run stays mild and settles within 24 hours. Keep running at that level rather than stopping, then add 10 per cent a week once two weeks have passed without a flare.
Terrain. Replace downhill and camber with flat, even surfaces for two to three weeks. Downhill is reintroduced last.
Strike pattern. Changing from a heel strike to a forefoot strike moves load from the knee to the calf and Achilles tendon. The change helps some runners with knee pain and creates calf problems in others, so we change cadence first and strike pattern only where the knee has not responded.
How is knee pain when running treated?
Knee pain when running is treated by combining the training changes above with progressive strengthening of the hip abductors, quadriceps and calf over 6 to 12 weeks, then rebuilding distance and hills in stages.
Patellofemoral pain. Strengthen the hip abductors and quadriceps through a pain-tolerable range, three sessions a week. The 2018 international consensus on patellofemoral pain places combined hip and knee exercise ahead of every other treatment, with taping and foot orthoses as short-term additions for some runners.
Iliotibial band syndrome. Strengthen the hip abductors and rotators, raise cadence, and cut downhill. Stretching or foam rolling the band gives short relief and does not change the cause.
Patellar tendinopathy. Load the tendon with isometric holds in the painful phase, then heavy slow resistance squats and leg press as the pain settles, and reintroduce speed work last. Rest alone weakens a tendon.
What we tell you at the assessment. Most runners keep running through treatment at a reduced load, and most are back to their previous distance within 12 weeks. Our runner’s knee physiotherapy in London page sets out the running assessment and the return-to-running plan we use, including video gait analysis where it changes the plan.
What makes knee pain when running worse?
Running through rising pain, stopping running entirely, and changing everything at once are the three habits that prolong knee pain when running.
Running through it. Pain that climbs above a mild level during the run, or that is still present the next morning, is a load the knee has not tolerated. The next run is shorter, not harder.
Stopping entirely. Two weeks of complete rest lowers the tolerance of the kneecap, the band and the tendon, and the first run back hurts at a shorter distance. Reduced running, not no running, is the treatment.
Changing everything. New shoes, a new strike pattern, new insoles and a new programme in the same week make it impossible to know what helped and add new loads to tissues that were not the problem. One change at a time, two weeks each.
When to get running knee pain assessed
Knee pain when running that has lasted more than two weeks despite a cut in load, that forces you to stop mid-run, that is present walking or on stairs, or that comes with swelling warrants a physiotherapy assessment, and no GP referral is needed. The assessment examines the knee, the hip and the way you run, and names the structure in one visit. Our knee pain physiotherapy service in London sees new knee assessments within days across all our clinics.
Note. Some running knee pain needs urgent medical care rather than physiotherapy. A knee that is locked and will not straighten, a knee you cannot put weight on, a knee that swelled within two hours of a fall or twist, a hot, red and swollen knee with fever, or calf pain and swelling with shortness of breath are reasons to call NHS 111 or go to A&E.
Common questions about knee pain when running
Should I stop running if my knee hurts?
No, in most cases. Reduce the distance and intensity to a level where pain stays mild during the run and settles within 24 hours, and keep running at that level while the knee is treated. Stop and get assessed if the pain forces you to halt mid-run, is present walking, or comes with swelling.
Why does my knee hurt only when running and not walking?
Running loads the knee with several times body weight on each landing and repeats one narrow range of knee bend thousands of times, which walking does not. A kneecap, iliotibial band or tendon with a reduced tolerance shows the problem under running load first.
Do I need new running shoes for knee pain?
Not usually. A worn-out shoe is replaced, and a change in shoe type is made one variable at a time. Shoes change where load lands but rarely fix a load problem caused by distance, hip weakness or stride length.
Will running damage my knees in the long run?
No. Recreational running is associated with a lower rate of knee osteoarthritis than a sedentary lifestyle in large reviews, and the knee adapts to running load when that load is raised gradually.
How long does runner’s knee take to heal?
Most runners with patellofemoral pain or iliotibial band syndrome return to their previous distance within 6 to 12 weeks of load management and hip strengthening. Patellar tendinopathy takes longer, often 12 weeks or more, because tendons adapt slowly.
Book your London knee assessment
Knee pain when running is a load problem in most runners, and the assessment finds where the load is going. You can book your first assessment for knee pain physiotherapy in London at any of our clinics in 60 seconds, with no GP referral needed.
References
- Collins NJ, Barton CJ, van Middelkoop M, et al. 2018 consensus statement on exercise therapy and physical interventions to treat patellofemoral pain. British Journal of Sports Medicine.
- Heiderscheit BC, Chumanov ES, Michalski MP, Wille CM, Ryan MB. Effects of step rate manipulation on joint mechanics during running. Medicine and Science in Sports and Exercise.
- Fredericson M, Wolf C. Iliotibial band syndrome in runners: innovations in treatment. Sports Medicine.
- Alentorn-Geli E, Samuelsson K, Musahl V, et al. The association of recreational and competitive running with hip and knee osteoarthritis: a systematic review and meta-analysis. Journal of Orthopaedic and Sports Physical Therapy.
- Malliaras P, Cook J, Purdam C, Rio E. Patellar tendinopathy: clinical diagnosis, load management, and advice for challenging case presentations. Journal of Orthopaedic and Sports Physical Therapy.
- NHS. Knee pain.
