What is runner's knee and how do I treat it?

Runner's knee — medically called patellofemoral pain syndrome (PFPS) — is dull pain around or behind the kneecap that worsens during running, going down stairs, or sitting for long periods. It's the most common running injury, affecting roughly 25% of runners annually. The root cause is almost never the knee itself — it's usually weak hip abductors and glutes allowing the knee to collapse inward during the running stride, which causes the kneecap to mistrack over the thigh bone. Treatment priorities: (1) Strengthen the glutes — clamshells, side-lying leg raises, single-leg bridges, monster walks with band. Do 3 sets of 15 daily. (2) Strengthen the quads with single-leg step-ups and wall sits, focusing on the VMO (inner quad). (3) Reduce running volume by 30-50% for 1-2 weeks while rehabbing. (4) Ice 15 minutes after any painful activity. (5) Foam roll the IT band, quads, and hip flexors daily. (6) Check your shoes — over 800 km, they're the problem. Most runners see improvement in 2-4 weeks with consistent glute work. If pain persists past 4 weeks or occurs at rest, see a sports physio to rule out meniscus or cartilage issues. Don't run through it — you'll compensate and hurt something else.