This is a beautiful article: a computational essay (with visualization) at its finest! I regularly think about the human masses and stored energy in the human body. I just asked Google Gemini:
is the tensional network in the human musculoskeletal network
overdamped, underdamped, or critically mapped?
Here is the AI's summary response:
The tensional network of the human musculoskeletal system—often
analyzed through the lenses of biotensegrity and myofascial chains—is
fundamentally an underdamped system that can be actively tuned toward
critical damping via neural regulation and muscle co-contraction.While
a pure underdamped system oscillates or bounces repeatedly, the body
utilizes its viscoelastic fascial matrix and active neuromuscular
control to maintain a perfect operational balance.
This is correct. Grok got it wrong. The interesting thing about our body's mass-spring complex is the co-activation of muscles to create and deploy stored energy. One small comment in the details about overdamping is telling:
[Overdamping] protects local areas from motion but makes the global
network slow and rigid.
Chronically holding tension in part of our body will make our body as a whole less efficient. The other way of stating that is through the model of impedance. A high impedance connection between body parts is good to isolate a particular part; low impedance connection allows for more energy efficiency and overall improved/optimal behavior of the system. MIT MechE Professor Neville Hogan has made a career talking about co-activation of agonist and antagonist muscles, starting with "Adaptive Control of Mechanical Impedance by Coactivation of Antagonist Muscles" (1984). That's also a wonderful computational essay; it just hasn't ever been wolframmed. Hogan is a roboticist; his specialty is "hard-soft robots" that are stiff enough to work with 100kg loads but can rapidly become soft enough to be no danger to nearby humans.
Tom Myers published Anatomy Trains in 2001; the 5e of this reference will be published later this year. This is a marvelous tensegrity-oriented mapping of the tensional lines in our musculoskeletal network. The fundamental theorem of Anatomy Trains is that the tension of a muscle's insertion spans through a bone and is the origin of a muscle on the other side of the bone. Those tensile forces are organized into 12 "myofascial meridians" -- long lines of tension. This is something that screams for a computational essay to selectively display those lines in a series AnatomyPlot3D expressions. I've been patiently waiting for someone to create those illustrations; I've recently realized that I should stop waiting and just do it. Myers's mappings are well-known in the industry, but are unknown by the general public.
Myers's mappings are the proper place to show the co-activations that Professor Hogan describes. The entire lines of arm pronation and supination -- the Deep Front Arm Line (DFAL) and Deep Back Arm Line (DBAL) -- are a superb example of Hogan's agonist/antagonist co-activation. I figured out a way to show that mass-spring system a few months ago. The trick is to torque the arm at the fist and then release it rapidly in a snap-like action. The CNS must be fooled to do the release in a snap, or it will try to micro-manage the release of energy. You can see a short video of the technique here.
I'll let you know when I have a draft of a computational visualization of Myers's Anatomy Trains.
