Knee pain when running is common, but it is not something you should simply ignore or “push through”.
Sometimes it is a short-term response to doing too much too soon. Other times, it can be a sign that your knee, hip, ankle, foot, or training load needs a closer look. The good news is that many running-related knee problems improve with the right advice, a clear rehab plan, and a sensible return to running.
In this guide, we’ll look at the common causes of knee pain when running, what different types of pain can mean, when to stop, and when to book a physiotherapy appointment.
Why do I get knee pain when running?
Running places repeated load through the knee. That is not automatically a bad thing. Knees are built to move, load and adapt. Problems often start when the load is higher than your body is currently ready for.
That might happen because of:
- a sudden increase in distance, speed or hill running
- returning to running too quickly after time off
- weak or under-conditioned muscles around the hip, thigh or calf
- reduced ankle, hip or foot control
- footwear changes
- running form changes
- previous injury
- not enough recovery between runs
NHS guidance notes that sudden knee pain is often linked to overuse or injury, and running-related knee pain can involve structures such as tendons, ligaments, cartilage or the kneecap joint.
Common causes of knee pain when running
1. Runner’s knee / patellofemoral pain
This is one of the most common reasons runners feel pain at the front of the knee or around the kneecap.
It may feel worse when:
- running downhill
- going up or down stairs
- squatting
- sitting with your knees bent for a long time
- increasing mileage
Patellofemoral pain syndrome is often called “runner’s knee” because it is common in runners and people who do sports involving repeated running or jumping. It usually refers to pain around the front of the knee or kneecap area.
This does not always mean something is badly damaged. Often, it means the knee is being overloaded or the way the kneecap is being loaded needs improving through strength, control and training changes.
2. Patellar tendon pain
Pain just below the kneecap can sometimes come from the patellar tendon. This tendon helps connect the kneecap to the shin and works hard during running, jumping, hills and faster sessions.
You may notice:
- pain below the kneecap
- stiffness at the start of a run
- pain when running uphill or accelerating
- discomfort with jumping, squatting or stairs
This is often linked to load. Reducing the aggravating activity for a period and building strength gradually is usually more helpful than complete rest alone.
3. IT band-related pain
Pain on the outside of the knee can sometimes be linked to the iliotibial band, often called the IT band. Runners may feel a sharp or tight pain on the outer knee, especially after a certain distance.
It can be influenced by:
- hill running
- cambered roads
- sudden mileage increases
- hip strength and control
- running mechanics
This is where a physiotherapy assessment can be useful, because the painful area is not always the only thing that needs attention.
4. Meniscus irritation or cartilage-related pain
The meniscus is cartilage inside the knee that helps with shock absorption and joint movement. Meniscus-related pain may be more likely if there has been a twist, deep squat, sudden change of direction, or a clear incident.
Possible signs include:
- joint line pain
- catching or locking
- swelling
- pain when twisting
- difficulty fully bending or straightening the knee
If your knee gives way, locks, becomes very swollen, or you cannot fully straighten it, it is worth getting assessed rather than waiting to see if it settles.
5. Knee swelling after running
A small amount of irritation can sometimes settle quickly. However, swelling is a sign that the knee is reacting to load, irritation or injury.
Swelling after running can be linked to several causes, including joint irritation, cartilage issues, ligament injury, bursitis, or inflammation. NHS guidance advises seeking help urgently if the knee is very swollen, hot, red, severely painful, deformed, or if you cannot weight bear.
6. Training load errors
Sometimes the main issue is not a specific structure, but the size of the jump in training.
Common examples include:
- going from 5km to 10km too quickly
- adding speed work and hills in the same week
- returning to your old pace after time off
- running too many days in a row
- changing shoes and mileage at the same time
The knee may simply be telling you that the current load is too much, too soon.
Should I stop running if my knee hurts?
You do not always need to stop running completely, but you should not ignore worsening pain.
A useful rule of thumb:
- Mild discomfort that warms up and does not worsen: you may be able to reduce distance, speed or hills and monitor it.
- Pain that changes your running style: stop and get advice.
- Pain that gets worse as you run: stop and reduce load.
- Pain that lingers into the next day: reduce training and consider assessment.
- Swelling, locking, giving way, or sharp pain: stop running and seek professional advice.
For minor sprains and strains, NHS advice often includes rest, ice, compression and elevation in the early stage, but the right approach depends on the injury and severity.
What can I try first?
If your knee pain is mild and there has been no major injury, you can start with a few sensible changes.
Reduce the load temporarily
This does not always mean doing nothing. It may mean:
- shorter runs
- flatter routes
- slower pace
- avoiding hills and speed sessions
- more rest days
- replacing some runs with lower-impact exercise
The aim is to calm symptoms without losing all fitness.
Check what changed recently
Look back over the last 2–4 weeks. Did you change your mileage, pace, shoes, route, surface or gym work?
Knee pain often makes more sense when you look at the recent training pattern.
Add strength work
For many runners, knee pain improves when they strengthen the muscles that help control the hip, thigh, knee and ankle.
This may include work for:
- quadriceps
- hamstrings
- glutes
- calves
- foot and ankle control
This is where strength and conditioning rehab can help, especially if knee pain keeps returning whenever you increase your running.
Consider your return-to-running plan
If you have had time off, your knee may need a gradual return rather than going straight back to your usual distance or pace.
Freedom’s return-to-running plan is a useful next read if you are trying to build back safely.
When should I see a physio for knee pain when running?
You should consider booking a physiotherapy appointment if:
- your knee pain has lasted more than 1–2 weeks
- the pain keeps returning when you run
- you are reducing your training but it is not improving
- you have swelling after activity
- the knee feels unstable or gives way
- you are preparing for an event and need a clear plan
- you are unsure whether it is safe to keep running
A physio can assess your knee, look at how you move, review your training load, and build a rehab plan that matches your goals.
At Freedom Physio & Wellness, we can support this through physiotherapy assessment and sports injury physiotherapy, depending on what you need.
How physiotherapy can help runners with knee pain
A good running-related knee assessment should look beyond the painful spot.
Your physio may assess:
- knee movement
- strength and control
- hip and ankle function
- balance
- running load
- previous injuries
- footwear and training habits
- return-to-running goals
From there, your plan may include:
- hands-on treatment where appropriate
- strength exercises
- mobility work
- running load changes
- return-to-running guidance
- advice on pacing, hills and speed work
- sport-specific rehab
For some runners, tools such as the AlterG anti-gravity treadmill can also help reduce impact while rebuilding running confidence and tolerance. If extra support is needed, knee bracing may also be considered after assessment.
Can I prevent knee pain from coming back?
You cannot prevent every running injury, but you can reduce the risk.
The key is to make your body more prepared for the running you want to do.
Helpful habits include:
- increasing mileage gradually
- keeping easy runs genuinely easy
- not adding too many new stresses at once
- including strength training
- taking rest seriously
- rotating routes and surfaces
- addressing small niggles early
- getting advice before pain becomes persistent
The best plan is not just to settle the pain. It is to understand why it started and build enough capacity so your knee can cope with running again.
Book an appointment
If you have knee pain when running and you are not sure what to do next, we can help.
Freedom Physio & Wellness can assess your knee, identify what may be contributing to the pain, and create a clear plan to help you return to running safely.
Book an appointment through our contact page and our team will point you in the right direction.
FAQ section
Is it OK to run with knee pain?
It depends on the pain. Mild discomfort that settles quickly may be manageable with reduced distance, pace or hills. Pain that worsens during the run, changes your running style, causes swelling, or lasts into the next day should be taken seriously.
What is runner’s knee?
Runner’s knee is a common name for patellofemoral pain syndrome. It usually causes pain around the front of the knee or kneecap and can be aggravated by running, stairs, squatting or hills.
Why does my knee hurt after running but not during?
This can happen when the knee tolerates the run at the time but reacts afterwards. It may be a sign that the total load was slightly too much, especially if there is stiffness, soreness or swelling later that day or the next morning.
When should I book a physiotherapy appointment?
Book an appointment if your knee pain lasts more than 1–2 weeks, keeps returning, causes swelling, affects your running style, or stops you training normally. You should also seek help sooner if the knee locks, gives way, becomes very swollen, or you cannot weight bear.
