My impression is many martial arts have existed for centuries. However a competent understanding of anatomy & physiology (which was one of the 3 breakthroughs that allowed modern medicine to being, along with anesthesia and antiseptics) occurred in the mid 19th century.
So what martial arts were created in the 20th century by people trained in human biology (doctors, biologists, etc) to take advantage of the better knowledge of how the human body works?
To my knowledge, none. Modern science tends to explain why this or that martial arts technique works, rather than make predictions about what should work. After millenia of trial and error in developing martial arts techniques, there’s not too much that hasn’t been tried already that modern science could fill us in on. We know now that being paralyzed with pain due to a blow to the lower left side under the ribcage or to the solar plexus is because of trauma to the liver or spasm of the diaphragm rather than the disruption of the target’s chi, but the techniques are centuries old.
Quite a few martial arts were founded in the twentieth century. These include krav maga and sambo (both originating in the 1930s) and brazillian ju jitsu in the early years of the twentieth century.
I am unaware of any art founded by scientists and doctors and doubt their knowledge would help them much. It is tough to repair a body, but very easy to harm one and humans have spent a great deal of time practicing that second set of skills.
There really aren’t any benefits of modern science or physiology regarding martial arts. People have been training to kill and beat each other up for thousands of years, if it was possible to harm someone while unarmed, it has already been discovered which parts are vulnerable through the natural evolution of fighting.
not sure about contributions of modern science, but I think that the exposure to the modern world helped purge some of the martial arts of dubious traditions. E.g. I know that the Russian “sambo” is just same old judo, only with somewhat revamped training regimen. One of the big innovations the Russians did was introduce lots of pushups, as simple as that. Less philosophy, less breathing in special ways, less sitting in the kneeling position - but MORE pushups and other strenuous physical training. Think of them as uncouth “young turks” - they didn’t know about the tradition, they didn’t care about it but they just wanted to get results the fastest. Also, come to think of it, judo itself is also a simplification and systematization of several previous schools created with the intent of getting results reasonably fast, almost in a McDonald’s fashion.
Another example of modernization would be introduction of boxers’ gloves and other protective gear into muay thai. Which presumably made sparring simpler, safer, more intense and hence useful.
This doesn’t exactly fit the bill but the Marine Corp LINE system was created by mixing many martial arts and having different moves studied by forensic pathologists for “medical feasibility.”
I’ve always thought of martial arts as being a study in body mechanics with little left to discover. A modern understanding of physiology could make them more effective but, it seems to me that it would be more of a supplement to the well known mechanics than the basis of something new.