First, my claim wasn’t “virtually horizontal” (although I said so in the past, before I had looked more closely); it was a 73-degree rise measured along the shin. Second, I think that amount of rise is consistent in all her steps, because AFAIK people who have studied the film frame by frame have said that this degree of lower leg rise (73 degrees along the shin) is, or seems to be, standard, including in the 1st and 3rd walk phases.
(I can’t remember where I read this though—I’ve been out of Bigfooting for five years, so my memory isn’t green on matters like this. As I posted a few comments upthread, it’s a pity there isn’t an online archive of every frame of the film, to quickly resolve matters like this.)
Emulating that degree of rise smoothly is tough (as a subject who tries it in the video “21 degrees between you and Bigfoot” illustrates), although my bud Matt Crowley is a contender, as he domo-d to me in front of my house. (I’m trying to get his walk on film, but my grant request to the National Instititute for the Humanoids hasn’t been green-lighted yet.)
Sometimes, as in the clip you linked to, that lift isn’t always visible to the eye or the camera, because the lower leg sort of flicks to its highest rise and rapidly changes into forward motion. Indirect evidence that this is so is how regular her gait seems to be; so if her shin lifts 73 degrees from the vertical in most of the frames (and the camera doesn’t capture the rise in others), it’s likely that the higher height was attained in all. Patterson was running the camera at its slowest speed, 16 frames per second, so it's possible that it wouldn't catch all the highest shin-rises.
I would say No, at least not as of nine years ago, based on this:
I couldn’t get the video to play, thanks to my obsolescent browser. But I’m old enough to remember his TV show, in which he often did his weird walk. This idea of a Groucho walk has been presented before. It’s obvious that what’s called, in science, a “compliant gait,” is similar to Patty’s bent-kneed gait.
Bigfooters have presented rebuttals. I forget most of them, but one of them was that it would be difficult for a human to maintain stability and gait-regularity during the lookback. The one I’ve come up with is that Heironimus claimed that his ordinary walk was virtually identical to his Bigfoot walk, which he demonstrated in street clothes in at least two videos. In those videos, “Heironimus's forward leg is straighter than Patty's, suggesting he's barely employing her "compliant" gait”; see the PhotoBucket image:
[qimg]http://i7.photobucket.com/albums/y254/RogerKni/BF%20Pattys%20%20Shank%20%20Stride%20%20and%20Sole/ef313719.jpg[/qimg]
But:
When interviewed, Heironimus said that on his first suit try-on he had no difficulty doing the Bigfoot walk that Patterson wanted. There was no mention of having to master an unusual gait:
But this claim is implausible, as the reader can verify for himself if he attempts to walk like the video’d 73° subject who raised his shank to the degree Patty did. He will find that he feels on the verge of losing his balance at the height of his leg-lift, and that it’s difficult to avoid lurching forward as he swings his leg forward, and then catching himself immediately afterwards, creating a jerky motion. In other words, it’s a difficult and complicated maneuver. But not according to Heironimus—indicating he’s never done it:
Sure it was easy, because in his street-clothes’ videos his shin lifted only the normal human 52 degrees.