Your knee starts clicking the moment you ramp up your runs, and suddenly every step feels like a question mark. We take that exact problem head-on, using a real-world scenario we see all the time: someone years removed from ACL reconstruction, excited to train for a 5K, but noticing new popping and clicking as mileage climbs.

We explain why the sound isn’t the whole story. Knee clicking often shows up when stability and strength haven’t caught up to impact demand, especially if post-surgery rehab ended early and the surgical leg never returned to 90 to 95% strength symmetry. Running makes this harder to hide because it’s a series of single-leg landings, and subtle compensations can repeat tens of thousands of times per week. Over time, that can drive irritation, mild swelling, extra joint fluid, and the kind of noisy feedback that gets your attention.

Then we shift into what to do next: the checkpoints we use to guide a safe return to running after ACL surgery, including restoring full range of motion (with knee extension as a priority), rebuilding quadriceps strength, improving eccentric control, balance, proprioception, and hip stability, and cleaning up running mechanics. We also share a practical interval run-walk approach to build impact tolerance without finishing swollen or sore, plus how we think about where the clicking comes from, including patellofemoral versus tibiofemoral sources and factors like ankle dorsiflexion and foot arch stability.

If you’re training for a 5K and your knee is getting loud, listen through, share this with a training partner, and subscribe for more practical performance rehab. After you listen, leave a review and tell us what your knee does when you run.