Aerobic Capacity is the foundation for endurance of any sort.
It's not the ability to run all day, that's a combination of qualities, but without it you'll blow up fast.
By decreasing your resting heart rate, increasing your anaerobic threshold, widening your aerobic window and improving your recovery rate between bouts of high end sprinting, you'll not only run all day but you'll be running over the grass well after your opponent has been broken.
The AEROBIC CAPACITY LEVEL 1 training manual is a 4 day a week program that lays the foundation for harder aerobic methods to come. Level 1 focuses on basic aerobic capacity with some intensity methods added to set you up for level 2.
By the end of the 4 weeks you should have dropped your resting heart rate by 3 - 5 beats.