The skill of running applies to the military. For those that are involved in Spec Ops, or similar communities, the skill of swimming the required stroke and all other aspects of your job are a necessity as well. You learn to shoot, fight, and survive. You must learn how to be efficient at everything else.
Follow the directions as indicated on each day's WOD. If you aren't recovering and hitting times that you should hit, take a day or two off... Recovery is why you get better, not more training! CrossFit Endurance S&C 5-6 times per week! The most successful people will be able to follow a CrossFit Endurance S&C schedule for 3 on 1 off or 2 on 1 off with heavy lifting and CrossFit Endurance as prescribed. This will not be accomplished in a week or two. If your job only requires you to run then you will only be choosing the run portion 2-3 times per week. Typically, 1 cycle, which is 1 interval(short or long interval), 1 tempo/stamina workout, and 1 more interval workout (short or long)... Once you have adapted to this training regimen, the implementation of a weight vest or ruck is essential 1-2 days a week with CrossFit Endurance. This should be flipped every other week with your interval and stamina workouts. Typically week 6 would look like this... Interval with weight vest, stamina, and interval (possible weight vest or ruck). Week 7 would be interval, stamina with weight vest/ruck, interval. These would be spaced out accordingly throughout the week as well.
If you are a single sport athlete other than running you will only need to employ 1-2 days of interval or 1 stamina session per week. Multisport athletes should train no more than 2 workouts per week per sport on this site. PERIOD! Follow anything else and you are not following this site correctly. You will also burn out, and fail to thrive. It is all too common a theme within these communities (Endurance and Military) that more is better. It is not, and we have the people that prove it. From Marines, SEALs, Rangers, Divers, Multisport, and Ultra distance athletes they have all had more success than previous training regimens. If you can put 100% into this training, you will reap the rewards of it. If you attempt to do more, you will never have the ability to give 100%. Save that for when you have to go to work or compete!
Yes, we know this is contrary to what everyone else is telling you...We aren't everyone.