I had the same problem (endurance when fighting) for MMA, and the workout I started doing has helped so much. I really do not run or do any cardio because I have horrible knees, so I get my cardio while weight training. I have run through a couple cycles with this workout, and it definately works. When I am not doing it, I tire out way faster when sparing. The workout I got is based off a workout that Rich Franklin does (
Rich's workout) Here is the workout I do:
The Idea The idea behind this workout is to keep the duration under 1 hour, while doing a full body workout. I do this 2 - 3 times per week, each day is with different exercises.
The Workout 20 exercises
3 sets of each, broken down into 4 rounds
15 reps of each exercise
Here is an example of one day:
Exercise
Wide Grip Pulldowns
Bench Press
Rope Hammer Curl
Machine Squat
Rear Delt (machine)
Bent Over Rows (under)
Incline Dumbbell Flys
Triceps Pressdowns
Calf Machine
Abs
Shrugs
Incline Bench
EZ Bar Curls
Lunges
Cable Raises (frnt)
Machine Row
Machine Bench
Overhead Tri Ext
Leg Curls
Abs
Basically I break each round down into 5 exercises, working most body parts. I do a round all at once (all 3 sets) before moving onto the next round. The idea is to use enough weight that on the 3rd set, you struggle to get 15. I usually only get about 12 on my last set.
This workout works both strength and endurance, and is very difficult in the beginning. I had 2 of my friends try it with me (both of whom had been working out for years) and both failed. The first puked after 15 minutes, and the other made it about 35 minutes.
While this builds endurance, it also builds strength. I weigh about 160 lbs, and decided to see if this workout would build actual strength in addition to endurance. Before I started doing the workout I dumbbell pressed something like 85 or 90 lbs for sets of 8, and now I am up to 105 for sets of 8.