For a Fighter is doing 3 sets of 8 - 12 reps sufficient?

Hi I'm doing a lot of kickboxing and looking into fighting soon so what i really want is endurance and strength I'm doing a lot of dumbbell and barbel work is 8 to 12 (upper body) reps sufficient for what i want to achieve as an athlete, or should i be more along the lines of 5 to 8 reps or 12 to 16 reps.