I studied several disciplines during my career. Mostly traditional Judo, Tae Kwon Do , and Escrima. Just before I retired, the USAF combat arms career fields adopted the Army Combatives training style which is a mix of several different disciplines. I also had the good fortune to train in the USMC martial arts program while I was assigned to CENTCOM, which is a joint command. Not being a Marine, I wasn't eligible to earn their belts, but I did get to train with them and learned quite a lot. The USMC program centers on using what is commonly available to someone in the field such as rifles, knives, e-tools, etc., and teaches the use of these tools in nontraditional ways.