Pain guide · Knee pain
A Baker's cyst is a soft, fluid-filled lump at the back of the knee. In adults it usually means something else is going on inside the knee, most often arthritis or a meniscus tear, and it tends to settle when that is treated. If it bursts, it can look just like a blood clot in the leg.
This guide gives the warning signs first, then what helps, what draining, injections and operations offer, and a gentle strength plan. The plan is our suggestion: no trial has tested exercise for the cyst itself.
Exercise is for pain that has been checked or is clearly mild and settling.
A Baker's cyst, also called a popliteal cyst, is a swollen sac behind the knee that connects with the knee joint. When the knee makes extra fluid, a one-way valve is thought to let fluid into the sac but not back out.
It may show more when you stand. It can feel tight or achy, make the knee hard to bend, and be worse after walking.
In adults a cyst is usually a sign of another knee problem. On 1,001 knee MRI (magnetic resonance imaging) scans, 94% of cysts came with damage inside the joint, most often a meniscus tear (83%) or cartilage damage (43%). Other scan studies link cysts with joint swelling, meniscus tears and arthritis.
In a rheumatology clinic, half were linked with osteoarthritis, and many of the rest with rheumatoid arthritis or gout.
Most often adults aged 35 to 70, and children aged about 4 to 7, in whom there is often no cause. Small cysts are common: about 1 in 5 knees without symptoms had one on MRI, and about 1 in 4 people with knee pain had one on ultrasound. In children without knee problems, 2.4% had one.
A GP examines the leg, looks for the cause and may arrange an ultrasound or MRI scan. Ultrasound is accurate: across 13 studies of 1,011 people, it picked up 97% of the cysts confirmed by surgery or tissue tests, with almost no false alarms.
If the cyst bursts, fluid leaks into the calf and causes pain, swelling, and sometimes redness and itching. An NHS trust leaflet estimates that about 1 to 2 in 20 cysts burst.
A burst cyst looks like a DVT, and the two can happen together: of 95 people found to have a cyst on scans for a suspected clot, 7 also had a clot. So a clot has to be ruled out first, usually with an ultrasound scan, which the NHS says should happen within 24 hours.
A cyst doesn't appear to cause clots: in 357,703 leg vein scans, cysts were slightly less common in people who had a clot.
It may go away on its own, especially in children, or when its cause is treated. The NHS says it can take a few months to a few years. A burst cyst makes symptoms worse for a few weeks until the swelling goes down, and cysts often come back after draining.
If a cyst comes from another knee problem, the NHS says symptoms usually get better when that problem is treated. For osteoarthritis, the National Institute for Health and Care Excellence (NICE) says offer everyone exercise tailored to them, such as muscle strengthening and general fitness. For a worn (degenerative) meniscus tear, 12 weeks of supervised exercise did as well as keyhole surgery at 2 years in 140 adults.
We found no trial that tests exercise for a Baker's cyst. The NHS lists physiotherapy among the treatments, and an NHS trust leaflet says keeping the knee moving and strengthening the muscles around it may help. The plan on this page is therefore editorial: the usual knee-strength plan, done in a comfortable range.
In small studies of people with knee osteoarthritis, draining the cyst and injecting a steroid shrank it and eased symptoms for weeks to months. Cysts often come back, especially complex ones: all 6 relapses in a study of 32 people were complex cysts, and in another study the benefit had faded by 6 months.
NICE says steroid injections for osteoarthritis give short-term relief, about 2 to 10 weeks, and should support exercise, not replace it.
The NHS says it's rare to have surgery to remove a Baker's cyst; operations more often repair damage inside the knee. Keyhole techniques are the most studied, but the evidence for them is low level. For a worn meniscus, our meniscus tear guide explains why exercise comes first.
Rest the knee, put an ice pack or a bag of frozen vegetables wrapped in a tea towel on it for around 10 minutes at a time every few hours, raise your leg on a pillow, and take ibuprofen or paracetamol if you can. The same helps after a burst cyst, once a clot has been ruled out. Crutches can help for a while if walking hurts.
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 isn't, or the swelling behind the knee is bigger or tighter, drop back one step next time: fewer sets or a smaller bend. The swelling check is our suggestion; this rule has never been tested for Baker's cysts. NICE says joint pain may rise when you start exercising with osteoarthritis, and regular exercise still helps.
New calf pain, swelling, warmth or redness is not a pain-rule question: stop and get a same-day check.
Start at the first stage. Each move opens a full guide with a 3D demo.
The first days to about 2 weeks, daily. All doses on this page are editorial starting points, because no trial has tested exercise for a Baker's cyst.
3D demoQuad set (static quads)Beginner · No equipment10 holds of 5 s, 2 to 3 times a day
Harder: Straight-leg raise
3D demoStraight-leg raiseBeginner · No equipment2 sets of 10 each leg
Easier: Quad set (static quads) · Harder: Leg extension
3D demoSupine heel slideBeginner · No equipment10 slow reps, once or twice a day · Bend only as far as the back of the knee is comfortable
Harder: Hip Windshield Wipers
3D demoGlute bridgeBeginner · No equipment2 sets of 10
Easier: Pelvic tilt into bridge · Harder: Glute kickback (quadruped hip extension)
3D demoStationary cyclingBeginner · Cardio machine10 min easy · Seat high, so the knee never bends fully
Harder: Air bike intervals
Move on when: The swelling behind the knee is no bigger the next morning and your calf feels normal.
About weeks 2 to 6, 2 or 3 days a week, in a comfortable range.
3D demoSit to stand from a chairBeginner · A bench or box3 sets of 8 to 12 · Higher seat first
Harder: Bodyweight squat
3D demoSeated knee extension (chair)Beginner · A bench or box + Something with weight3 sets of 10 to 15 each leg
Easier: Quad set (static quads) · Harder: Leg extension
3D demoStep-upBeginner · A step3 sets of 8 to 10 each leg · Low step
Easier: Low step-up · Harder: Dumbbell step-up
3D demoWall sitBeginner · A wall3 to 4 holds of 20 to 40 s · Shallow
Easier: Straight-leg raise · Harder: Spanish squat (band squat hold)
3D demoSlow calf raiseBeginner · A wall3 sets of 12
Easier: Seated bent-knee calf raise (soleus raise) · Harder: Standing dumbbell calf raise
3D demoSide-lying leg raiseBeginner · No equipment3 sets of 12 each side
Easier: Lateral band walk · Harder: Lateral band walk, band at the feet
Move on when: 12 sit-to-stands and 10 step-ups each leg leave the swelling and the ache no worse the next day.
From about week 6, two strength days a week. Then move on to the knee arthritis or meniscus tear plan if that is your cause; NICE says keeping exercise up over the long term increases the benefit.
3D demoSplit squatIntermediate · No equipment3 sets of 8 each leg · Hold a support; go only as deep as is comfortable
Easier: Bodyweight squat · Harder: Reverse lunge
3D demoLeg pressBeginner · Strength machine3 sets of 8 to 12 · Gym option, limited depth
Harder: Bodyweight squat
3D demoDumbbell goblet squatIntermediate · A dumbbell3 sets of 8 to 12 · To a box
Easier: Bodyweight squat · Harder: Back squat with bands
3D demoSingle-leg standBeginner · A wall3 holds of 30 s each leg
Easier: Tandem stance and heel-to-toe walk · Harder: Single Leg Reach Matrix
3D demoSingle-leg calf raise from a stepIntermediate · A step + A wall3 sets of 8 to 10 each leg
Easier: Slow calf raise · Harder: Single-leg pogo hops
3D demoLateral band walkBeginner · A band3 sets of 10 to 12 steps each way
Easier: Hip abduction machine · Harder: Lateral band walk, band at the feet
Move on when: Add a little load or a harder option, one change at a time, while the swelling stays settled.
Bending can be hard with a cyst, and the back of the knee can feel tight, especially when you stand. Use a range that feels comfortable and build it back as the swelling settles. If walking makes it ache afterwards, take shorter walks spread through the day.
Get a clot ruled out first. Then rest, ice and raise the leg, and expect a few weeks before the swelling goes down. Going back to the first stage as the calf settles is our suggestion.
| Habit or position | Why it matters | Instead |
|---|---|---|
| Deep squats, kneeling and full knee bends while it's tight | Bending can be hard with a cyst, and the back of the knee feels tight. | Bend only as far as is comfortable; stand up from a higher seat. |
| Long walks or long spells of standing that make it ache | Symptoms can be worse after walking. | Shorter walks spread through the day, or cycling with a high seat. |
| Carrying on through sudden calf pain or swelling | It could be a burst cyst or a clot, and they look alike. | Stop and get a same-day check. |
| Massaging or stretching a painful, swollen calf | A clot has to be ruled out first (our caution). | Rest, ice and raise the leg once a clot is ruled out. |
| Ice straight on the skin | The NHS advice is an ice pack wrapped in a tea towel. | An ice pack wrapped in a tea towel, about 10 minutes at a time, every few hours. |
| Expecting draining or an injection to fix it for good | Cysts often come back. | Treat the cause, with exercise for arthritis or a meniscus tear. |
A gentle leg strength routine with no jumping: sit-to-stands, step-ups, wall sits, bridges and calf raises.
20 minBeginner7 movesA bench or box, A stepA 30-minute joint-friendly circuit built like the GLA:D and ESCAPE-pain programmes: a gentle warm-up, chair, step and band strength moves, balance, then stretches.
30 minBeginner14 movesA bench or box, A stepA 20-minute seated workout for older adults who cannot stand for long: marching, leg and arm strength, posture, and sit-to-stands that lead back to standing.
20 minBeginner11 movesA bench or box, Something with weightA soft, fluid-filled lump at the back of the knee, connected to the knee joint. In adults it usually means something else is going on in the knee, most often arthritis or a meniscus tear.
Usually not, and it may get better on its own or when its cause is treated. The serious part is telling a burst cyst from a blood clot, so sudden calf pain or swelling needs a same-day check.
You can't reliably, and neither can a doctor by looking: both cause calf pain, swelling and redness, and both can happen together. A scan settles it, and the NHS says a suspected clot should be scanned within 24 hours.
Yes, in amounts that don't make it ache afterwards; symptoms can be worse after walking, so build up gradually. If you have osteoarthritis, exercise for strength and general fitness is part of its treatment.
Thigh-strengthening exercises, gentle knee bending and cycling suit it, and the NHS lists physiotherapy among the treatments. Go easy on deep squats, kneeling and full knee bends while the back of the knee is tight, and stop for any sudden calf swelling.
Often, especially in children. In adults it can take a few months to a few years, and it usually settles when the cause is treated.
Draining fluid and injecting a steroid can shrink it and ease symptoms for weeks to months, but cysts often come back, especially complex ones. It works best as a support for treating the cause.
Rarely: surgery to remove the cyst is uncommon, and operations more often repair damage inside the knee. For a worn meniscus tear, exercise did as well as keyhole surgery in a trial.
No. In over 350,000 leg vein scans, cysts were slightly less common in people with a clot. A clot and a cyst can still happen together, which is why calf symptoms need checking.
It might be, but after surgery a clot has to be ruled out first. Follow your surgical team's advice, and see our knee replacement guide for the warning signs.
Exercise education, not a diagnosis or treatment plan. It is written from the guidelines and studies listed above; review by a clinician is pending. If your pain follows an injury, is severe, is getting worse, or comes with any warning sign listed on this page, get it assessed. Health disclaimer.
