Why do my knees hurt going down stairs?
Going down loads the knee far harder than going up. Your quadriceps have to lower your bodyweight under control, and the force travelling through the kneecap can reach several times what you weigh. Pain going down but not up nearly always points at capacity and control rather than damage.
What you’re feeling
The asymmetry is the whole clue, and it’s worth being precise about:
- Going down hurts; going up is fine, or noticeably better
- An ache around or behind the kneecap rather than at the joint line
- Worse on steep stairs and on downhill walks
- You’ve started holding the handrail, or going down sideways, without deciding to
- Sometimes a wobble or shake in the leg on the way down
- Often worse the day after a long descent than during it
Uphill pain, or pain deep inside the joint with swelling, suggests something else — check the warning signs.
Why it’s happening
Descending is an eccentric task: the muscle produces force while lengthening. It’s the hardest thing you ask a quad to do, and four things make it harder:
Quads that can’t lower you under control
On the way up, the muscle shortens and it’s comparatively easy. On the way down, it has to pay out slowly against gravity while the kneecap is pressed into the thigh bone. When that capacity is short, the joint absorbs a load spike on each step. This is the main event.
A hip that lets the knee drop inward
Watch your knee as you step down. If it drifts toward the midline, gluteus medius isn’t stabilising the thigh bone and the kneecap gets pulled off its groove exactly when the load is highest. Very common, and easy to see in a mirror.
An ankle that won’t bend
Descending requires the front leg’s ankle to bend to absorb the landing. If it can’t, the knee travels further forward and takes more of the shock. It’s worth testing even if your ankles feel entirely fine.
More descending than you’re used to
A new flat with three flights. A hilly holiday. A running route with a long downhill. Descending is the part of any route that people never count, and it’s the part the knee notices.
Stop and see a doctor if any of these are true
- The knee gives way or buckles under you
- It locks and won’t fully straighten
- Swelling, especially if it came on within hours of an injury
- A hot, red, swollen joint, particularly with fever
- Pain that began with a twist and a pop, or a direct blow
Buckling and locking suggest something structural inside the joint and need examining. A hot swollen joint with fever needs same-day attention.
How to fix it
Build the exact capacity that’s missing — controlled lowering — and take the pressure off by sorting the hip and ankle around it. Modify the stairs while you do, but don’t avoid them entirely.
Wall sit or Spanish squat
A static hold at a depth that doesn’t hurt. Isometrics reliably reduce knee pain and start loading the quad without asking it to move through the range that’s irritating. This is the entry point even if it feels far too easy.
45 seconds × 5, dailySlow step-downs
Stand on a step, lower the other foot toward the floor over three seconds, tap the heel, come back up. This is the exact skill you’re missing, trained deliberately. Start on a step low enough to feel trivial and add height across weeks.
8 reps × 3 each side, every other daySplit squat
Long stride, lower the back knee toward the floor with control. Builds the quad through a fuller range once step-downs are comfortable, and it makes any left-right difference impossible to ignore.
8 reps × 3 each side, twice weeklySide-lying hip abduction and banded walks
Both target gluteus medius. Side-lying builds it; banded walks teach you to use it while weight-bearing. This is what stops the knee falling inward on each descending step.
12 reps × 3, every other dayKnee-to-wall ankle mobility
Foot a hand’s width from the wall, drive the knee forward to touch it without lifting the heel. If you can’t reach, that’s your restriction and it’s feeding straight into the knee. Work just at the edge of possible.
10 reps each side, dailySix to twelve weeks for real strength change. In the meantime, going down one step at a time or holding a rail is sensible load management, not defeat — the point is to keep using stairs at an intensity that doesn’t leave you worse tomorrow.
Knees that handle stairs
The eccentric progression above, guided and properly scaled, with a no-equipment version.
Start the free classQuestions people ask next
Is my cartilage worn out?
Usually not, and even if a scan showed wear it wouldn’t explain the pattern. Cartilage changes are found in enormous numbers of people with no knee pain at all. Pain that appears only when descending is a loading and control story, and it responds to strength work regardless of what the scan says.
Should I avoid stairs?
Reduce rather than avoid. Complete avoidance lowers the knee’s tolerance further, so you feel better for a fortnight and worse when you next meet a staircase. Take them slower, use the rail, take one at a time — but keep taking them.
Why does up feel fine but down doesn’t?
Because they’re different jobs. Going up shortens the quad under load, which is comparatively easy. Going down asks it to lengthen under load while the kneecap is pressed hard into the thigh bone. The second is far more demanding, so it fails first.
Does the cracking sound matter?
On its own, no. Noisy knees are extremely common in people who have never had knee pain, and the loudness tells you nothing about the state of the joint. Noise combined with locking, swelling, or giving way is worth investigating; noise by itself isn’t.