Body Position Classification System

October 28, 2016 2:45 PM

Is there some system to describe the ways that the human body can be positioned? Something like the International Phonetic Alphabet where you can notate the full range of human speech sounds, but for the human body? I have a project where I want to compare different body positions mathematically.
posted by gregr to Science & Nature (12 answers total)

Benesh Movement Notation?
posted by warriorqueen at 2:48 PM on October 28, 2016 [2 favorites]

yeah, dance notation is the closest i know (of which the above is one).
posted by andrewcooke at 2:51 PM on October 28, 2016

There are ergonometric tables of measurements that may be in the area you're looking for. Seems oriented towards real world issues more than the possible ranges of motion.
posted by sammyo at 3:17 PM on October 28, 2016 [1 favorite]

Yes: Anatomical terms of motion
posted by ludwig_van at 3:23 PM on October 28, 2016 [2 favorites]

I was also going to suggest dance notation, and since you say you want to compare body positions mathematically, here's a computational system, based on Labanotation:
Dance: A Declarative Language for the Control of Humanoid Robots

posted by at at 3:34 PM on October 28, 2016 [1 favorite]

Response by poster: The dance notation is interesting, but seems like it would be difficult, for example, to record some of the complicated yoga poses with those systems, and the systems don't seem to have numerical components that would make for easy comparison.

Anatomical terms of motion is pretty thorough, but it doesn't have a system to describe the the whole body's position? I guess you could list out every body part that can move and each type of motion in that part and list an angle or something, but that seems pretty inelegant?
posted by gregr at 4:17 PM on October 28, 2016

My first suggestion was going to be labanotation. Given your additional feedback: You might want to look at the file formats that motion capture systems use to encode pose data over time. There are many, but BVH is kinda the grandparent, in my experience. They tend to store a hierarchy of joint angles representing each articulated part of the body. It's hierarchical -- the rotation of a forearm is expressed in terms of its angle relative to the 'parent' upper arm, etc. (Note that this stuff assumes you're either using software to manually pose the a 'rig' representing a body, or you're using a motion capture system to capture live performance -- in this case you'd probably need to make a rig and manually animate it?)
posted by Alterscape at 4:53 PM on October 28, 2016 [1 favorite]

I looked into this problem a few years back when I wanted to write down notes on martial arts forms. Like the others I found labanotation to be the closest good option, but still not really the best. I ended up inventing my own notation just for my own purposes. But since then I have run across people using labanotation from time to time for everything from medical biomechanics to robotics, and never seen anyone using the others. So it's at least out there as something standard-ish.
posted by traveler_ at 7:58 PM on October 28, 2016 [1 favorite]

After your update re yoga poses, I can tell you that during my yoga teacher training, we did in fact have to learn how to exactly describe in writing how to do advanced poses. It was all based on joint flexion and extension, adduction and abduction, and internal and external rotation. For example, tree pose would contain the instructions "abduct, flex and externally rotate the right hip joint, flex right foot and press into left thigh." Eagle arms would be "extend arms 90 degrees at shoulder, adduct until arms cross, flex elbows 90 degrees, etc."

Are you looking for a way to mathematically describe because you want to program yoga flows, or was that a random example you just gave?

(I am not familiar with dance notation or labanotation; I just happen to have a bit of practical experience with yoga notation.)
posted by instamatic at 4:40 AM on October 29, 2016

I guess you could list out every body part that can move and each type of motion in that part and list an angle or something, but that seems pretty inelegant?

Yes, that's pretty much exactly what we did, if the above descriptions were not clear enough. Though in the case of yoga teacher training, there was educational value in evaluating body position joint by joint, which might not be true of a programming/math challenge.
posted by instamatic at 4:44 AM on October 29, 2016

Response by poster: @instamatic you guessed right, I want to use the notation system and some computation to generate weird new yoga flows by comparing body positions.
posted by gregr at 9:24 AM on October 29, 2016

Have you researched existing yoga flow apps? Pocket Yoga Builder might be a good place to start. They sort of do this-- if you start from a position they will highlight a range of positions that make sense to do next. For example,
Mountain > extended mountain or chair
Down dog > 3 legged dog or lunge, but not mountain or chair

I don't know how they do it under the covers, but I'm betting that it's not mathematical but instead driven by yoga knowledge.
posted by instamatic at 9:57 AM on October 29, 2016