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.