About two years ago [1] my knees got so bad I couldn't walk more than about ten minutes. This wasn't new to me; in Spring 2009 my knees started hurting a lot after morris dancing, so I stopped doing that. [2] In Fall 2009 my knees started hurting after bicyling, but I needed to bike to get to work so I didn't stop bicyling until November when we moved (for unrelated reasons) to somewhere closer to work where I could take the bus. Off and on over the next few months my knees would hurt a lot, I would cut back on activities, and I went to a phyisical therapist a few times. The pain would go away, then come back. When it got bad enough that I couldn't walk (or dance!), however, I decided I should take it seriously.

I started doing several different things:

• Stretches and exercises every night before I went to sleep.
• Fixing how I walked so that my feet weren't turned out.
• Walking barefoot or in fivefingers and learning how to toe-strike.
• When wearing shoes that were awkward for toe-striking, trying to heel-strike as weakly as possible.
• Standing up at work, using a standing desk.
• Walking more.

Not all of these are things I started doing because of my knees (though most are) but they're all things that I think might be a part of why my knees don't hurt. I don't know the contribution of each one, so you'd think it might make sense to experiment, but I'm too risk-averse.

Update 2015-02-05: I think most of the benefit comed from the stretches and exercises. When I've been lazy and stopped doing them my knees have started hurting again, and then they get better when I start again. I've also stopped doing much of the other things on the list, so it probably wasn't them. It's hard to say for sure with just n=1 and no control, though.

[1] I remember being sad that I couldn't dance at NEFFA and being worried that I wouldn't be able to walk to may day on the Charles. This was Spring 2011.

[2] I remember trying to walk from Back Bay home to Medford after the Easter tour, and being too cheap to take public transit. It was painful, but I was trying to be stoic. Which was stupid. I gave up when we got to Central Square.