I would've thought the training incorporated less self-harmful techniques than that.
Some techniques taught can be directly self-harmful if done full force like ridge hands (elbow prone to hyperextension) or stomping/kicking with your foot turned out like your kicking a soccer ball (femur wants to go past the tibia in that case). Other training is harmful as well such as hand hardening work like in kung fu movies where they punch into sand progressing to harder objects. It works...at a high cost.
Most often though it is just repetitive use injuries from doing high repetitions of strikes/techniques year after year. I always think about risk vs. reward in my training. It doesn't make sense to injure yourself in training (or in combat) in order to avoid getting injured by the other guy. I've certainly had my share of contusions (get bruises every session), inadvertant groin whacks and mild tweaks/sprains. Nothing more serious though.
It's hard to paint this with a wide brush, but I'd say traditional MA, especially those where you do lots and lots of striking repetitions in the air and on bags and/or combat sports will be more likely to result in overuse injuries. The reality based arts (Krav Maga, Haganah, TFT, Jim Wagner, SPEAR (Tony Blauer), Southnarc ect.) would be less likely to have a long term toll like that in my opinion.
As spacecoastguy wisely said, moderation and think about what you are doing. Lots of stuff out there doesn't make any sense biomechanically...the Chinese systems are big offenders with stuff like striking with your wrist! (no thanks
). Yeah, you can ring someone's bell by whacking their temple with your wrist...but you can get the same result with a hammer fist and no downside. Same with the ridge hand mentioned above, just turn your palm up and strike with the blade edge of your hand or ulnar side of the forearm...same result, no biomechanical downside.
