To build strength bro do alot of compound muscle movements. Excerises like squats, bench press, front shoulder press, dead lift and power cleans. This will help you build your strength and also help you build muscle. Now stength is one thing, but to fight you need muscle endurance. The difference is with strength training your sets are high and reps low like, 5x3-6 for every excercise. Endurance your sets are low with your reps high like, 3x12-25. Me I train for endurance like this. I pick either upperbody or lower body to do and then I pick 5 different excerises to do and each excerise for 1min then move right into the next and so on until the last excerise without not rest then take 1min rest period then do it again for 5 sets. So it is like a fight with 5 5min rounds. Also run for 3 days a week and jump rope for 2 days a week. with running start out with running for 15mins then work up to 45 mins, don't worry about distance to start with you will worry about that when you can run for 45mins.