Female hormones and knees
Canadian researchers think they may understand why female athletes are so much more likely to damage their knees than male athletes. It comes down to the time of the month.
http://tinyurl.com/d46lt4
Full circle cycling
Whenever I'm struggling on a ride, James always reminds me to use the full circle of my pedalling. This means you draw the biggest circle possible with your pedal so as to maximise your output. It makes sense really. I also find that when I'm tired, just focusing on the pull/upward section of my pedal stroke for a bit gives my quads a little bit of a rest.
"Soft face"
This is a concept I read about on Pat Carroll's website (see links tab). The idea is that no matter how much you're hurting, you keep your face soft and relaxed and then that will help keep the rest of you feeling better. I used to be a shocker for strained and painful facial expressions and so have tried this out. I find that it really does help me feel better.