I started out as a boxer. Studied Tae Kwon Do for a few years after college. Then back to boxing. In my late 30's I trained in MMA, not to compete, just to learn some techniques. Also studied with a martial arts expert to learn disarm and retention techniques as well unarmed defense against a knife and offensive techniques. His style was a mix of many classical styles. He trained for over 40 years.
I was a light heavyweight as a boxer (amatuer). When I first began to study martial arts I knocked my instructor out with a left hook when he said to come at him full speed. He was a second degree black belt and in shape at 160 ibs. I outweighed him by 15 ibs and was in excellent condition too. It was a good punch but it wouldn't have knocked me out or anyone else I've faced in a ring....my two cents at least.
Here's my observation on martial arts and hand to hand combat in general. Learn a few good techniques and become very adept at them. Really learn to throw a punch correctly, learn an arm bar technique and a few chokes and escapes. It takes time to learn them all and compete. You are better off learning a few things and practicing them often.
Another thing I've observed is the first punch ends the fight 95% of the time. Most people give up after one punch because they've never been hit hard before. I've never seen an untrained person take a 3 punch combination from an amateur boxer with some skill and not go down. Boxer's are always the most sought after guys on a crew of bouncers....at least they were in my younger days.
Every Saint has a past...every Sinner a future.