I used to have severe knee issues, which gave me a lot of pain and weakness, to the point of my knee collapsing if I moved the wrong way. Then my 20s I learned tai chi, which is basically the alignment and muscle-building suggested in the article. That helped quite a bit. I had to train my knee to stay in line with the rest of my leg, and build enough balanced muscle to hold it there. Then, in my 30s I discovered anti-pronating shoes. Wow. That solved 99% of the rest of it! The knee problems return as the shoe foam breaks down (about every 3-4 months at my usual 10-15km per day). So, replacing my shoes often is important. For my Camino this summer (yes, at 40-- this process to knee health took me a long time!!) I learned a little trick for hills: "sit back" when descending steep inclines or stairs. Imagine your posture of sitting in a hard-backed chair (ie "sitting," not "crouching"): the shins/calves/knees stay directly above the ankles--not in front of the feet--and your "behind" hangs out, well, behind...(not above your feet as in crouching). This takes the pressure off the knees and puts it into the quads and glutes, which are much bigger stronger muscles. Try it out, moving very slowly at the start, paying close attention to your body. It may feel like you are leaning back "too far" at first, but you want to be able to feel the strain shift away from your knees and towards your thighs/butt, as you assume the position. Once you find the right position, you can move at normal speed. Another related tip: take many very short steps, instead of long strides. This will help you hold your posture more easily, and ironically, give you more speed.
Buen Camino!
