Do not listen to Coach D or anyone else who is telling you that glue activation is a myth or the sign of a charlatan.
I'm a mid-40's lifelong runner, and a few years ago I had a bad case of runner's knee. My ortho recommended quad strengthening isometric exercises, which I did diligently to no effect. When that didn't work, he told me all he could offer was semi-annual cortisone shots.
I then was fortunate to find a really good PT who took the time to diagnose my muscle imbalances and weaknesses. It turns out I had very weak (or "inactive") gluteus medius, which allowed my knee to "collapse" inward under load, causing my kneecap to track improperly and lead to my knee pain. A concerted program of glute strengthening completely eliminated the pain. Furthermore, I can now feel those glute muscles working when running, which I never could before. I also just feel stronger, more stable, and springier somehow in my stride.
A simple test to see if you have the same problem is this: Do a single-leg squat, trying to keep your kneecap pointed directly over your second biggest toe. If your knee tends to move medially as you do your squat, or it takes great effort to prevent it from moving medially, your gluteus medius is weak, and you will probably benefit from strengthening it. Good luck.