Penny was limping for some time this year, and we often look at her as she walks towards us, trying to work out whether the limp is still there.
So I was fascinated when I came across a teaching module, presumably for vets, on studying a dog's gait for lameness. It uses optical motion capture data. Reflective round markers are placed at joints and key locations on dogs' bodies and then the dogs walk - I guess on a treadmill. A video of the movement shows only the markers and the difference between healthy gait, displasia and cruciate problems is clearly shown.
I found it at a site called What's New - which, by the way, is a great find for me as it seems to be a lhasa apso site and I'm convinced that Penny's ancestry includes lhasa apso.