I was wanting to watch the Channel 4 show on Frankel and Sir Henry Cecil but to my dismay I couldn't find if someone had streamed it so I gave up. Before I did however I stumbled across this older Racing UK footage of a track gallop.
It was pretty sweet watching him go by the good horses Bullet Train and Jet Away as if they were stuck to a post. I have already done some rough measurements of his average maximal stride but there were some other features of his stride that I was struck by in watching the video (slowed down on Kinovea).
Firstly, he has zero curl of his forelegs. What do I mean by that, here is a photo of a horse with some serious mechanical inefficiencies in terms of 'curl'.
I hope that you can see from the photo at the top and the angle measurement at the bottom that this horse has some real 'curl' to his foreleg. There are some times that a horse can get away with this but generally speaking this isn't an efficient biomechanical feature to have, especially for soundness. Take a look at Frankel
His forearm comes back to a vertical position and his cannon barely closes under 90 degrees. The second feature of interest, and it is related to the first, is the distance from nose to hoof at extension for Frankel is extraordinarily low. Again, here is our hapless grey...
And here is Frankel....
The angle of the photo taken for Frankel is slightly different as he was getting away from the cameraman so I couldn't quite get it when his off fore was at vertical stance like I did in the other frame, but you get the idea. He has what looks to be outstanding extension of his foreleg and combined with (or is it because of?) his 8m stride length made him poetry in motion. I also tracked down some similar video of a young horse having a breeze down in Florida as a two-year-old.