Knee pain when lunging: the kneecap, the tendon, the back knee, stride and depth, and what helps

What a lunge asks of the knee, and what no study has countedEmerging evidence

A lunge puts most of your weight through one bent front knee (in a lab study of 26 men doing Bulgarian split squats, the front foot took 84% of the force), while the back knee drops towards the floor. The force behind the kneecap rises as the knee bends. In a lab study of 20 healthy adults, it peaked at about 5.1 times body weight in a lunge, against 1.7 for a low step-up, 2.5 for a squat to 60 degrees, 4.5 for a full-depth squat and 5.4 for running, and the patellar tendon was loaded too. Forward lunges add a braking step, which raised the load on the knee in two small lab studies.

These figures come from lab studies of healthy people, not people with knee pain, and no study counts how often lunges cause knee pain or what the causes are. So the map on this page is built from what each condition is known to do, lunge lab studies and health-service pages. Pain usually comes when the load, or a jump in it (a new class, a lunge challenge, many more sets, heavier weights), gets ahead of what the knee is used to; an NHS trust says kneecap pain "is often related to a sudden change in activity levels".

Sources 1, 2, 3, 4, 5, 6, 7

The front knee: kneecap pain and the two tendonsStrong evidence

Kneecap pain is pain around or behind the kneecap brought on by loading a bent knee, such as squatting, stairs, running or jumping, and an NHS trust's leaflet names lunging too. The best simple test is pain during a squat. It is common in young people: 7% to 28% of adolescents, and 12% to 15% of military recruits.

One sore point at the lower tip of the kneecap, worse with jumping, landing and deep or fast lunges, is usually the patellar tendon (jumper's knee). One point at the top edge, worst in deep bending, is the quadriceps tendon: an expert viewpoint says that up to one in four athletes with pain at the front of the knee have it at the top of the kneecap, and that in very sore cases, deep bending may need to wait. In a growing child, a tender bump below the kneecap is usually Osgood-Schlatter disease, which NHS inform says hurts "when you kneel".

Sources 8, 9, 7, 10, 11, 12

The joint line, arthritis, and the back kneeEmerging evidence

A meniscus tear usually follows a twist in sport, the NHS says, but from mid-life a worn (degenerative) tear can come on slowly, often with no clear injury, and is often found by chance on scans of painless knees. Knee arthritis brings a stiff ache, often in both knees, and the National Institute for Health and Care Excellence (NICE) diagnoses it from 45 without an X-ray when the pain comes with activity and morning stiffness lasts no more than 30 minutes.

Pain in the back knee is one of the commonest searches about lunges. No study has measured the back knee in a lunge, so this is our reading: where it touches the floor, the pain is usually pressure. In a lab study of 10 people kneeling on one knee, most of the pressure went through the tendon below the kneecap and the bump at the top of the shin rather than the kneecap, and knee pads lowered the peak but didn't remove it. A soft swelling over the kneecap is bursitis; the NHS advises padding and breaks when kneeling. In the Bulgarian split squat, the back leg does little of the work (about 16% of the force), so pain at the front of the back thigh or hip is usually a stretch of the hip flexors.

Sources 13, 14, 15, 16, 17, 18, 19, 1

"Lunges hurt but squats don't", and the different lungesEmerging evidence

A lunge puts more of the load through one knee and asks for balance and braking, and a deep lunge bends the front knee further than many people squat. In the lab study of 20 healthy adults, a squat to 60 degrees loaded the kneecap about half as much as a lunge. That is our reading of why lunges can hurt first. Another lab study, of 20 trained men, called the Bulgarian split squat hip-dominant, with less knee movement than the back squat, so the studies differ in emphasis.

The forward lunge loaded the knee more than the reverse lunge in 9 men (1.38 against 1.18 newton-metres per kilogram, about 17% more) and put more force behind the kneecap in 20 women. Stepping out to the side loaded the kneecap more than a forward lunge at the deepest part, in 18 people. Jumping lunges add landing. All of these are lab studies of healthy people.

Sources 3, 20, 5, 6, 21, 2

Clicking, and what a scan showsStrong evidence

Painless clicking is normal, the NHS says; a knee that locks, gives way or clicks painfully needs advice. Kneecap and tendon pain are diagnosed from the story and an examination, NICE diagnoses arthritis without imaging from 45, and a European consensus on worn meniscus tears says a magnetic resonance imaging (MRI) scan isn't the first test. After an injury, a short checklist (the Ottawa knee rule) decides whether an X-ray is needed: it picked up 98.5% of broken bones across 6 studies. A Dutch guideline reconsiders the diagnosis if kneecap pain hasn't improved after 12 weeks of structured exercise.

Read scan reports with care. From 40, cartilage defects showed in 43% and meniscal tears in 19% of knees without symptoms across 63 studies, and in 991 people aged 50 to 90, 61% of those with a meniscal tear on MRI had had no knee pain, aching or stiffness in the previous month.

Sources 22, 9, 23, 16, 14, 24, 25, 15

How it usually goesEmerging evidence

No study follows knee pain from lunges. Kneecap pain is often slow: in 310 people, 55% had not recovered well at 3 months and 40% at 12 months, and pain for more than 2 months at the start was the strongest warning sign, so start the exercises early. An NHS trust expects improvement "over a 3- 6 month period" with rehab, and in 151 young teenagers who changed their activity and then exercised, 86% reported success at 12 weeks (with no comparison group). Of the fifth of one group who replied 5 to 8 years later, 57% had not recovered well, but 48 of the 50 who had an X-ray showed no arthritis.

Osgood-Schlatter disease improves over months but can last 12 to 24 months, and NHS inform says sport "is not likely to cause any permanent issues or problems". A worn meniscus tear often settles with exercise. No one can promise a date.

Sources 26, 7, 27, 12, 28, 29

Exercise is the treatment for kneecap pain, with hip and knee work togetherStrong evidence

In a Cochrane review, exercise eased pain during activity by about 1.5 points out of 10 against no exercise (5 studies, 375 people), and hip and knee exercise together eased it by a further 2.2 points against knee exercise alone (3 studies, 104 people). The evidence was of very low quality but consistent, and two international consensus statements and the United States guideline recommend hip and knee exercise together. The newest guideline, from the Netherlands in 2025, says quadriceps or hip exercise "for at least 6 to 12 weeks", in a programme "which continuously adjusts to the patient's pain intensity".

In military recruits, quadriceps weakness predicted kneecap pain, while hip weakness didn't (18 studies, 4,818 people). NHS trust leaflets for kneecap pain set strengthening at 3 sets of 8 to 12 of each exercise (Sherwood Forest) and 3 to 4 times a week with rest days between (Royal Berkshire). None of these trials or leaflets tested lunges as a treatment, or a change to the lunge.

Sources 30, 31, 32, 9, 23, 33, 34, 7

Forward against reverse lunges: lab studies in healthy peopleEmerging evidence

In 9 healthy men, the forward lunge gave a bigger turning force at the knee than the reverse lunge (1.38 against 1.18 newton-metres per kilogram) and at the hip (2.09 against 1.84), with the knee bending about as far in both, and the authors suggest starting with the reverse lunge and building to the forward lunge. In 20 women without knee pain, the forward lunge put more force behind the kneecap, and loaded it faster, than lunging backwards. Neither study included people with knee pain.

Sources 5, 6

Step length, depth and a low platform: lab studies in healthy peopleEmerging evidence

In a group of lab studies by one team, the force behind the kneecap rose as the knee bent further. With a short step (the knee about 8 to 10 cm past the toes), it was higher between 70 and 90 degrees of bend than with a long step, in 18 people lunging with a weight; in another study of 16 people, a long step loaded the kneecap a little more early and late in the movement. Lunging in place, without stepping out and back, loaded it less in the shallower part, and lunging up onto a 10 cm platform loaded it less than at ground level. The team's suggested order is a small range (0 to 50 degrees) first, then deeper, then a long step up onto a platform, then ground level.

In 20 men doing split squats with a barbell, a longer step lowered the turning force at the knee and raised it at the hip, and a step about one leg's length suited strength training. In 10 healthy people, kneecap stress was lowest squatting from 45 degrees of bend to straight and doing knee extensions from 90 to 45 degrees, which is why stage 1 uses a high bench and a part-range leg extension. These are healthy people in a lab, so the lunge advice on this page is our reading of them, not a tested treatment.

Sources 35, 21, 36, 2, 37, 38

Knees past the toes, leaning forward and where you hold the weightEmerging evidence

In 7 weight-trained men squatting, stopping the knees passing the toes cut the turning force at the knee by about a fifth but raised it at the hip about tenfold. In 25 healthy women lunging, letting the knee go in front of the toes raised patellar tendon stress by 11.1%, though the knee also bent further. So knee travel is a dial to turn down for a while with a sore kneecap or tendon, not a source of harm.

In 10 adults, leaning the trunk forward in a lunge made the hip muscles work harder, without changing the knee's work in the abstract we read. In another 10 adults, carried weight raised the force behind the kneecap and in the tendon in step with the load, most with weights at your sides or in the hand on the front-leg side.

Sources 39, 40, 41, 42

Foot width and a knee that drifts in: thin evidenceMixed evidence

In 15 trained men, lunging with the feet in line raised side-to-side sway by about 23% against a hip-width stance, without changing muscle activity. That study only measured sway, in a lunge held still with the back knee straight, so the common cue to keep your feet like "railway tracks, not a tightrope" is editorial: sensible for balance, but not tested for pain.

A knee that drifts inwards on landing predicted later kneecap pain in two small studies (76 teenage girls, of whom 8 developed it, and male military cadets), and across 25 trials changes in knee and hip movement went along with changes in pain, which shows a link, not a cause. The United States guideline advises against using a mirror or video to correct alignment during these exercises.

Sources 43, 44, 45, 46, 9

Tendon pain: staged loading, with walking lunges in the middleEmerging evidence

In the largest patellar tendon trial (76 athletes), staged loading (still holds, then slow heavy strength, then springy loading), kept at 3 out of 10 or less, was compared with eccentric squats: at 24 weeks, pain during exercise was 2 out of 10 against 4. Its supplement lists walking lunges and step-ups as the stage 2 exercises when no machine is available, and split jump squats in stage 3. For the quadriceps tendon, an expert viewpoint advises loading into deep bending as it settles, but says very sore tendons may not tolerate it early on.

Sources 10, 11

A worn meniscus and arthritis: exercise firstStrong evidence

In 140 adults with a worn meniscus tear, 12 weeks of exercise did as well as keyhole surgery at 2 years, and a European consensus says surgery isn't the first treatment. In deep bending the menisci slide backwards (an MRI study of 10 people), so deep lunges are the last part of the range to bring back with a sore meniscus (our reading).

For knee arthritis, NICE calls exercise a core treatment and warns that pain may rise when you start; across 139 trials (12,468 people), exercise improved function by about 11 points out of 100 and may have eased pain by about 9. The UK arthritis programmes (Arthritis UK and ESCAPE-pain) use step-ups, squats and sit-to-stands rather than lunges, so lunges are optional for arthritic knees and come later, in a short range.

Sources 28, 14, 47, 16, 48, 49, 50

Braces, injections and surgeryStrong evidence

The United States guideline says don't prescribe knee braces, sleeves or straps for kneecap pain, while foot orthoses (insoles) may help for a few weeks. For arthritis, NICE says steroid injections give "short-term relief (2 to 10 weeks)". For a worn meniscus, keyhole surgery isn't the first treatment. A complete tendon tear is repaired, which is why the warning signs send a pop with a knee you can't straighten for help the same day.

Sources 9, 31, 16, 14

Your lunge for now (written steps)

Our 3D figure can't show all of these. They come from lab studies of healthy people, NHS trust leaflets and our lunge guide; the load figures behind them weren't measured in people with knee pain, and where a step is our suggestion or editorial, it says so. No trial has tested a change to the lunge for knee pain.

• 1. Split squats (both feet planted) and reverse lunges before forward and walking lunges. The forward lunge loaded the knee more than the reverse lunge in two small lab studies.
• 2. Take a step of about one leg's length, so your front knee doesn't travel far past your toes at the bottom. A short step raised the kneecap load in the deepest part.
• 3. Go less deep at first and build depth over the weeks, or lunge up onto a low (about 10 cm) step before lunging at floor level.
• 4. Feet hip-width apart, like railway tracks rather than a tightrope, and the front knee over the middle toes. This cue is editorial: the only study measured sway, not pain.
• 5. A slight forward lean of the trunk moves work to the hips (our suggestion while the kneecap is sore).
• 6. Hold one dumbbell at your chest rather than weights at your sides for now.
• 7. The back knee: lower it under control, stop a few centimetres short of the floor, and put a folded mat under it. This is editorial, from our reading of a kneeling study; the NHS advises padding when kneeling.
• 8. Fewer lunge sets with rest days between, keeping the rest of your training going (our suggestion). An NHS trust suggests strengthening "3 to 4 times per week with rest days in between".

Sources 5, 6, 2, 36, 37, 43, 41, 42, 17, 19, 7

Growing knees, arthritis and a knee replacement

For a teenager with Osgood-Schlatter disease, NHS inform says most can carry on with their activities, finding a balance, and some need to stop completely for 2 to 4 weeks; a pad under the back knee, or split squats without the knee down, can help them keep training (our suggestion). A child or teenager with knee pain and a limp needs checking the same day: the NHS says hip problems can sometimes be felt in the thigh or knee.

With knee arthritis, the UK programmes use step-ups, squats and sit-to-stands, so lunges are optional and come later, in a short range that passes the pain rule. After a knee replacement, the NHS says don't kneel on your new knee until your doctor says you can. Across 36 studies, about 37% of people could kneel a year after the operation and 48% after 3 years, so lunges with the back knee down may stay hard; split squats that stop short of the floor are the usual swap.

Sources 12, 55, 16, 49, 50, 56, 57

Back to your usual training (written steps)

No study has tested how lunges come back after knee pain, so these steps are our suggestion unless a source is named.

• 1. One change at a time: depth, then the type of lunge (reverse, forward, walking), then load, then speed or jumping lunges.
• 2. Add load in small steps, about 2% to 10%, when the last set has reps to spare and the knee is fine the next morning (the American College of Sports Medicine's steps for healthy lifters, as our squatting guide uses).
• 3. Side, curtsy and deficit lunges come back after forward lunges are comfortable: stepping out to the side loaded the kneecap more in a lab study.
• 4. Jumping lunges last, and only once landings are comfortable (our knee pain when jumping guide).
• 5. Keep two strength sessions a week with hip and knee work for a few months after the pain has gone.
• 6. If it flares after a big session, go back a stage for a few days, not to nothing, then build again.

Source 2