Why does my knee hurt when I run?
Chelmsford Physio • May 26, 2026
Whether you are a seasoned runner, or new to the sport, knee pain is common and should not be the reason you stop running forever. Despite popular belief, running does not appear to be bad for your knees studies would suggest, in fact, recreational running can be really positive for joint health, for many different reasons.There are so many different reasons you can get pain when running, but we will focus on patellofemoral joint pain for this article.
The patellofemoral joint is the joint in which the knee cap (patella) joins to the thigh bone (femur). When the quads are relaxed, you can wobble your knee cap about as it sits above the joint, but when you contract your quads, the knee cap is stabilised by both the muscles and the joint itself. This joint allows the force of the quads to be transferred to the shin bone (tibia) and therefore strighten the knee. The patella sort of works as the fulcrum, a bit like a see saw.
As you run, you repeatedly straighten the knee, which puts pressure through the underside of the knee cap and into the femur. This is normal, and what it is designed to do. But sometimes the back of the knee cap can become irritated, and this is patellofemoral pain.
Patellofemoral pain is usually not a ‘damage’ to the joint, but more of an overload of a structually sound kneecap, so surgical intervention is not usually indicated and will normally resolve with physiotherapy, although it can take a long while to get better with a structured rehab program, expectations here are key!
So why does it occur? Well, there are many different reasons, but these can be categorised into 2 types:
1) Increased load – this is that you put more pressure through the joint than it is used to. So could be because of increased mileage, increased speed, more hills or more sessions a week.
2) Decreased capacity – the health of our tissues vary dependent on some internal factors too. For example, the amount of sleep you have had, your nutrition/hydration, levels of stress, decreased support from the quads to support the knee, feeling unwell or a reduced strength due to recent inactivity.
Symptoms of patellofemoral joint pain
Pain in patellofemoral joint pain tends to be located on the front of the knee, although it is usually really difficult to poke. So it can be frustrating to try to describe where the symptoms are, are usually feel they are "inside the knee somewhere".
Pain is usually worse going down stairs rather than up and tends to come on while running and gradually get worse the further you run.
Pain that may get worse after prolonged periods standing, running or engaging in other impact sport. In the most severe cases everyday activities such as using the stairs and kneeling can be very painful.
Crunching, clicking or a grating sensation that you can feel and/or hear in your knee. It may get worse when you bend or straighten your knee. This is normal but can be concerning for some patients.
How do I resolve my patellofemoral pain?
Well, obviously this sort of depends on what the initial cause was! Usually though the first thing to do is decrease (not stop!) the amount of load going through the knee. This could be by adjusting the way you run, or adjusting the amount of exercise/running your currently doing. Effectively, try not to do exercise that makes your pain go above 3/10 during or after. It’s also often a good idea to begin exercises for the gluteal muscles and the quads, initially simple things that don’t cause pain like straight leg raises and side lying abductions. These will tend to be comfortable but would also need to be progressed towards squatting and lunging style exercises as able.
Essentially the aim is to offload the knee a little to settle the pain, and then build up the amount of pressure through the knee gradually again with exercise and a graded running plan.
So initially, try to reduce the aggravating factors and start some quad and glute exercises to see how these go and if still struggling give us a call.
Jon McComish PGc BSc (Hons)
Clinic Director & Chartered Physiotherapist
Chelmsford Physio
Riverside Leisure Centre, Victoria Rd, Chelmsford CM1 1FG
In modern physiotherapy, clinical expertise remains fundamental, but technology is transforming how we assess, monitor and guide rehabilitation. One of the most valuable innovations is the use of force plate technology, and at our clinic we utilise the VALD ForceDecks to provide objective, reliable data throughout a patient’s rehabilitation journey. Rather than relying solely on observation or subjective feedback, ForceDecks enable us to accurately measure how your body produces and absorbs force. This allows us to identify movement deficits that may not be visible to the naked eye, track progress over time, and make evidence-based decisions regarding exercise progression and return to activity. What are VALD ForceDecks? VALD ForceDecks are dual force plates that measure the forces generated through the feet during a wide variety of movements. Using highly sensitive load cells, they capture detailed information about strength, balance, power, asymmetries and movement strategies. Common assessments include: Countermovement jumps Squat assessments Single-leg balance testing Sit-to-stand testing Isometric strength testing Landing mechanics Hop testing for return-to-sport decisions Within seconds, the software analyses hundreds of metrics that provide clinicians with objective insight into a patient’s physical performance. Why Objective Assessment Matters Traditional physiotherapy assessments rely on observation, manual muscle testing and patient-reported symptoms. Whilst these remain valuable, they can miss subtle deficits that increase the risk of delayed recovery or re-injury. ForceDecks allow physiotherapists to quantify movement rather than estimate it. For example, following an ACL reconstruction, a patient may appear to squat evenly. However, ForceDecks often reveal significant offloading of the surgical limb, reduced eccentric control or delayed force production. These hidden compensations can then become specific treatment targets. Objective measurements also improve communication between clinician and patient. Seeing measurable improvements in strength or symmetry provides reassurance that rehabilitation is progressing, even when symptoms fluctuate. Monitoring Progress with Precision One of the greatest benefits of ForceDecks is the ability to track rehabilitation over time. Instead of simply asking whether someone feels stronger, we can measure improvements in: Peak force production Limb symmetry Rate of force development Jump height Landing forces Balance performance Weight distribution This enables rehabilitation programmes to be progressed based on measurable performance rather than arbitrary timelines. Improving Return-to-Sport Decisions Returning to sport too early remains one of the biggest risk factors for re-injury. Research has consistently demonstrated that persistent strength deficits and movement asymmetries can remain long after pain has resolved. ForceDecks help clinicians identify these deficits before an athlete returns to competition. Objective testing can assist with: Assessing readiness to return to running Evaluating landing mechanics Measuring explosive power Identifying left-right asymmetries Monitoring fatigue Reducing the risk of subsequent injury Rather than relying on a single test, ForceDecks contribute to a comprehensive return-to-performance assessment that combines physical capacity with clinical reasoning.
On 23 and 24 October, I represented Chelmsford Physio at VALDCon London, held at Lord's Cricket Ground. VALD makes the ForceDecks force plates and DynaMo dynamometer we use in clinic to measure strength, power and left-right balance. The two days brought together physios and sports scientists from elite sport, including England cricket, British Athletics and professional football. They shared how they use testing to guide rehab and return to sport. Here are the takeaways most relevant to you, and how we're bringing them into the clinic.
Based at Riverside Leisure Centre in Chelmsford, we are excited to introduce our ultrasound-guided injection service.
