The Return of Gait Analysis

Author

Paul Skallas
February 08, 2023

There are things that are Lindy, get forgotten, and then come back. For example, American food was fresher and healthier in 1915 then it was in 1980. The canned food, tv dinners, bad coffee and explosion of fast food dominated the landscape. Today, you can buy fresh food of almost any type now in grocery stores. It came back. Similarly, hunter-gathers studied animal and human gait in order to survive. Gait analysis disappeared for a few thousand years, and now studying gait is back for the same reason.

How often do you notice how exactly you walk? It’s something I don’t notice much at all except for a few instances in my life. When I lived in France, I noticed the French walking more with their pelvis forward in contrast to Americans walking with their shoulders forward. I was meeting a friend at a cafe and saw a silhouette of a person in the distance walking toward me. I instantly recognized my friend’s gait and knew it was him. So there probably is something happening unconsciously with noticing how people walk that we don’t really.

Animals do it all the time. My cat is able to differentiate between people traversing the stairs to my front door (purely by the sound). The pacing and weight is usually very unique from one person to the next. She will consistently jump up from my lap to greet a beloved family member at the door, but never gets up for guests. You can try out if you have a dog, they can identify their owners at a distance by gait, for instance when looking for you at a crowded dog park.

Here’s a good (and funny) video on an orthopedic review of gait:

Hollywood and De-Aging

Movement and gait is something fundamental to us. It’s hard to fake it. People can get plastic surgery, take hormones and do all types of anti-aging treatments but the way you move betrays your true age. Joe Biden is a healthy 80-year old man who has had some work done, but he does indeed look like he does have the fragility of an 80 year old man.  You can’t hide that.

Hollywood is making movies with older stars but using new de-aging technology. Old stars still make a lot of money for them and new stars are not as recognizable. I couldn’t name you 10 famous movie stars under 35, quite frankly.

The de-aging technology looks good if the actor doesn’t move. Once they move, you start noticing that it looks off. Think of Harrison Ford in Indiana Jones or Al Pacino, in his 70s playing 40 year old Jimmy Hoffa in the recent Scorsese film. You can tell this isn’t how a 43 year old man moves.

Huner-Gatherers and Gait Analysis

it is likely that hunter-gatherers had a more keen awareness of human and animal gait due to their reliance on hunting for survival. They may have had to observe and track various animals in their natural environments, and a good understanding of animal gait could have been crucial for successful hunting. Moreover, living in a world of hostile tribes and hand-to-hand weapons means recognizing the gait of a member of another tribe is crucial for survival.

People today may have less exposure to the natural world and may not have the same level of familiarity with animal gait. I buy my food at the store, I don’t hunt it. I am not a member of a tribe, I live in a neighborhood. Studying gait isn’t tied to my survival. But it was to hunter-gatherers. That’s exactly what research on cave art suggests.  

Horses (and most four-legged animals) move their legs in a particular sequence as they walk. The “foot-fall formula,” as it’s called, goes LH-LF-RH-RF, where H means ‘hind,’ F means ‘fore,’ and L and R mean ‘left’ and ‘right,’ respectively. Of the 39 ancient cave paintings depicting the motion of four-legged animals that were considered in the study, 21 nailed the sequence correctly, a success rate of 53.8%. Due to the number of combinations of how a four-legged animal’s gait can be depicted, the researchers state that mere chance would lead to a 26.7% rate of getting it right. Cavemen artists knew what they were doing.

When the researchers looked at 272 paintings and statues of four-legged animals made during modern times but before the 1880s, such as a famous horse sketch by Leonardo da Vinci, it turned out that these more recent artists were much worse: They only got the sequence right 16.5% of the time. Remarkably, even the 686 paintings and statues studied that were made more recently than 1887, after scientists knew for sure how four-legged animals walked, still got it right just 42.1% of the time.

While there has been observations on gait by Aristotle, Hippocrates, and Galen. Today, gait analysis is back with advances in technology, research and study. The biggest governments and most well-funded universities are studying it for military, business, health and identification purposes. It’s as important today as it was in hunter-gatherer periods.

But how it is used today is important to know.

Gait Recognition for Security

There is a lot of attention be paid to facial recognition. It’s been part of science fiction forever. It’s also being used to unlock your phone as well. You have one face and no one else has it. But if an organization wanted information on an individual without intrusive measurements like a face scan, fingerprint, or iris scan, they would just record your gait from afar.

Individual humans do not have the same gait. Each person's gait is unique. And walking patterns can provide more than a simple identification, like health issues. With facial identification people need to look into a camera. Cooperation is not needed for gait recognitionIf I was a government that really wanted to identify people, I’d choose gait. It’s much easier. And we’re seeing that now.

A Chinese company is piloting a gait tracking system in Chinese cities that can mobilize tens of thousands of real-time cameras to recognize a person's gait and help police nab suspects

Gait recognition is slowly being added as part of the Biometric surveillance system worldwide. Other governments and corporations are getting involved.

Gait recognition technology is developing very fast. So fast in fact, that it doesn’t even involve recording someone with a camera. This is where it gets a little scary…

Gait Recognition Technology Without Cameras

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