A knee injury
Go to A&E (accident and emergency) if you've injured your knee and it has changed shape, it becomes very swollen very quickly, you felt a pop or snap, you can see bone sticking out, or it's bleeding heavily. Don't drive yourself: ask someone to take you, or call 999 if the pain means you can't move your leg to get there.
Get advice from NHS 111 now: you cannot move the knee or put any weight on it, or it is very painful, badly swollen or has changed shape, or it locks, gives way or clicks painfully. A pop, quick swelling and a knee that gives way point to an ACL injury: our ACL injury guide says what to do.
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A hot, swollen knee
Get advice from NHS 111 now: a hot, red or swollen knee with sudden severe pain, a very high temperature, or feeling hot, cold or shivery. This can be a joint infection.
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After a fall or a twist
You hurt your knee and cannot take 4 steps, or you are 55 or over and have injured it: get it checked the same day for a broken bone.
Get advice from NHS 111 now: after a twist, your knee won't go fully straight, or something blocks the last part of straightening, even if you can still walk on it. A torn piece of meniscus caught in the joint can do this, and it needs checking promptly.
Signs of a torn ligament: you felt or heard a pop, the whole knee swelled within a few hours, or it gives way, feels loose or bends further back than the other knee. Get it assessed promptly, the same or the next day: our ACL, PCL and outer knee ligament (LCL) guides explain what happens next.
A swollen, painful leg
Same day (urgent GP appointment or NHS 111): throbbing pain in one leg (rarely both), usually the calf or thigh; swelling in one leg (rarely both); red, blue or darkened skin; or swollen veins; or sudden worse pain and swelling around a lump at the back of the knee (a possible clot or a burst Baker's cyst).
Call 999 or go to A&E if breathing suddenly becomes difficult, if pain in your chest or upper back comes on suddenly with breathlessness or a very fast heartbeat, or if someone passes out. Do not drive yourself. It can be a blood clot that has reached the lungs.
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See a GP or physiotherapist
- Outer knee pain that started with a twist, or comes with swelling or locking: that is not typical of IT band syndrome. After a blow or a twist, see our LCL sprain guide.
- Knee pain that has not improved within a few weeks of looking after it at home. Many areas offer NHS physiotherapy without a GP referral.
- Numbness, tingling or weakness that travels down the leg from the back. That points to a nerve (sciatica) rather than the knee.
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If it isn't easing
Outer knee pain that still stops you running after about 6 to 8 weeks of hip strengthening and less running: see a sports physiotherapist or sports medicine doctor (our suggestion, from the 6-week programmes in the studies).
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The knee pain rule
Rate your knee pain from 0 to 10 during and after exercise. In the pain-monitoring model used in knee trials, 0 to 2 counts as safe, up to 5 as acceptable and above 5 as too much. Aim for 0 to 3 most of the time.
By the next morning your knee should be back to its usual level. If it is not, drop back one step next time (fewer sets, a shallower range, a lower step), not to nothing. Over the weeks pain should hold steady or ease; that last check is our suggestion rather than a tested rule.
Sharp, catching or giving-way pain, or new swelling, is a reason to stop and get it checked.
Chest pain or fainting: call 999
Call 999 if:
- You get sudden pain or discomfort in your chest that doesn't go away; it can feel like squeezing or pressure, burning or indigestion.
- The pain spreads to your left or right arm, or your neck, jaw, stomach or back.
- You have chest pain and feel sweaty, sick, light-headed or short of breath.
- Someone faints while exercising, can't be woken within 1 minute, or has chest pain or a pounding, fluttering or irregular heartbeat.
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Unusual breathlessness
Call 999 or go to A&E (accident and emergency) straight away for severe difficulty breathing (gasping, choking or not able to get words out), a chest that feels tight or heavy, pain that spreads to your arms, back, neck and jaw, lips or skin turning very pale, blue or grey, or sudden confusion. If you're more short of breath than usual, or your heart is racing, fluttering or skipping beats, contact NHS 111.
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Very flexible joints
If you're hypermobile, don't use mobility work to push further: the NHS says "do not overextend your joints just because you can". See a GP if you think you have joint hypermobility syndrome: for example, your joints keep dislocating, or you keep getting sprains, strains, pain or stiffness.
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During yoga
A joint pain that is sharp, gets worse during a session, lingers into the next day or changes how you move is a reason to use an easier version, and to see a GP or physiotherapist if it keeps happening (the rule in our plans). Muscle soreness for a day or two after something new is normal. In a hot class, stop if you feel dizzy, sick or unwell; our hot yoga guide lists the signs of heat illness.
Before you start
The NHS advises getting advice from a healthcare professional first if you have a health problem, an injury or symptoms, or have recently had a heart attack or an operation.