I've noticed the mention of bike fitting and various related pains and injuries but I didn't know the basics of frames... so I came across these on YouTube in my quest and found them helpful. Thought I'd share them. I can't vouch for technical correctness so would appreciate the comments of more knowledgeable folks.
Note: I've got an engineering background so I liked these, but it might easily bore someone else.
Cool stuff. Georgena Terry the founder of Terry Bicycle is in this video. I have built up and worked on a few of her bikes, back in the day. Georgena modified the "funny bike" designs from the mid 80s pursuit and time trial bikes, now banned from racing in most bicycle racing organization. I don't remember the frame builder she hired to build and design her bikes, but I do remember reading something about him once. The design is very affective at accomplishing the desired fit for the very small rider. The disadvantage to this design is that most bike shops do not have 24" road tubes, tiers and wheels in stock. The rider also has to carry two inner tubes as replacements. Check out the Hand Built Bicycle Frame Builders Of Chicago group. There you can ask chicago frame builders any question on frame geometry.
P.S. If you fined other videos like this, could you post it there. The frame builders would greatly appreciate it.