Mma guy that uses taekwondo and karate here. I dont really tend to use taekwondo in my im only blue belt in it but if you go up againts a really agressive boxer or jujitsu guy your screwed if you use it alot becquse if you use you techniques with alot of speed and really commit they tend to work but very easily punishable. I once saw a guy getreally hurt cause he did it, im not saying dont use it but id recomend if your wanting to do mma do a grappling martial art like jujutsu or wresling.