Is knee pain after sport normal in children?

Most knee pain in young athletes is growth-related — conditions like Osgood-Schlatter — and settles with sensible load management rather than signalling lasting damage. A few signs, however, mean you should see a professional: a limp that does not clear with warm-up, visible swelling, pain at rest or at night, the knee locking or giving way, or one-sided pain that worsens week on week.

When should I take my child to a doctor for knee pain?

See a professional if the pain makes them limp, the knee is swollen, it hurts at rest or wakes them at night, the joint locks or gives way, or the pain is one-sided and getting worse over several weeks. Also seek advice for any knee pain that has not eased after two to three weeks of reduced load.

What is Osgood-Schlatter disease?

Osgood-Schlatter is a common growth-related cause of knee pain in active children, felt as tenderness and sometimes a bump just below the kneecap. It is linked to growth and training load, usually settles as the child matures, and is generally managed by reducing jumping and running load rather than stopping activity altogether.

Guides · Injuries & Health

My child has knee pain after sport — should I worry?

By Marian Pitel, S&C coach·Last reviewed 29 May 2026·5 min read

Short answer

Most knee pain in young athletes is growth-related and settles with sensible load management — not a sign of lasting damage. But a few signs mean you should see a professional: a limp that won't clear, visible swelling, pain at rest or at night, the knee locking or giving way, or one-sided pain getting worse week on week.

Why children's knees hurt in the first place

Children are not mini-adults, and their knees prove it. In a grown athlete the weak link is usually the ligament or tendon. In a growing child it's the growth plate — the soft, still-forming area near the joint where the tendon attaches. That's why so much youth knee pain clusters just below the kneecap: it's the spot taking the pull every time they sprint, land or kick.

The common, mostly-harmless culprits have names — Osgood-Schlatter being the one you'll hear most. It shows up as tenderness, and sometimes a small bump, just under the kneecap, and it tends to flare when training load jumps or during a growth spurt. It's uncomfortable, it's worth managing, but on its own it isn't damage and it usually settles as the child matures.

The five signs worth acting on

Here's the line I use with the parents I coach. Aching is one thing; these five are different — if you see them, get it looked at rather than waiting it out:

A limp that doesn't clear with warm-up. Stiffness that eases after ten minutes is usually fine. A limp that stays — or appears mid-session — is not.
Swelling you can actually see. One knee looks puffier than the other. Joints shouldn't swell from ordinary training.
Pain at rest or at night. Pain that shows up when they're sitting still, or wakes them, behaves differently from load-related soreness.
The knee locks or gives way. A joint that catches, locks, or buckles under them needs assessing.
One-sided pain getting worse week on week. Most growth-related aches settle or stay steady. Pain on one side that's climbing is the pattern to respect.

What's usually fine — and what to do this week

Tenderness below the kneecap that eases when you ease the load, general achiness after a growth spurt, soreness that's even on both legs and settling — these are the everyday signs of a body that's growing and working, not breaking.

The fix is rarely “rest completely”. It's load. The evidence points to roughly 125 jumps a week as a healthy ceiling for a young athlete — and I routinely see children doing more than that in a single session once you count training, matches and PE together. So count the load across everything, not just the sessions you can see. Pull the jumping and sprinting volume back, keep them moving in low-impact ways they enjoy, and don't let anyone tell a sore child to “push through”. If it hasn't eased in two to three weeks, that's your cue to see a professional.

The one thing I'd never do

Treat a child's pain as a test of character. “When you can't go on, push harder” is the worst advice in youth sport — I've seen a boy given extra jumps as punishment for not finishing a set end up with a bone injury in the thigh. Pain in a growing athlete is information, not weakness. Read it.

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This guide is for understanding and decisions at home — it isn't a diagnosis. If something worries you, or any of the five signs above are present, see a doctor or physiotherapist.