Thanks Bruce. That book is great to hear about since I've only ever seen a muso shinden ryu book written in Japanese.
As for achy knees, I can only speak from personal experience (no medical expertise) and say that what works for me, other than occasional ice packs and ibuprofen, is that I take a glucosamine / chondroitin supplement for joint flexibility. You're supposed to take it consistently for something like 4-6 weeks before you notice any improvement. A more unusual treatment: back in my schooldays, I made some post-soccer-practice visits to the sports/physical therapist for an ultrasound massage on a damaged knee. Also, don't know if it's relevant to you, but I try to stay away from spending too much time in extremely high heels.