After JD was Temporarily Totally Disabled and told he would never run or do martial arts again, he recovered and whipped all the high school football players on consecutive days in a 2 mile run.
After recovering from the disabling injury to his feet JD ran a lot to get back into fighting shape. Then 'Super' Dan Anderson told him to spend that running energy kicking instead. In photo below JD is finishing an 11 mile race averaging about 7 min 40 seconds per mile. As an experiment to demonstrate how effective KICKING is for overall fitness, JD had done NO RUNNING for a year but resumed running for only 1 week to prepare for this race. His previous best time was just under 7 min mile average. Conclusion: Kicking is awesome exercise! Most humans couldn't finish the race with only 1 week of running training let alone run it in the 7+ min area average time. 
Finishing a 10k race
JD knew that competing in many different types of competitions would put him at a disadvantage against those who focused their training on that particular type of activity. His goal was to learn from the experiences what ever they were and make him a better overall martial artist. He had to learn to accept getting whipped by the girls too.
JD no longer recommends running for martial arts conditioning unless they are training for a sport like boxing where kicks are not allowed.  Kicking is harder work, is superior technical training and results in a much better ability to reach out,  deliver serious power, and end a fight.