First off, you must realize that it is a long season and all your training takes a serious toll on your body causing fatigue, usually realized down the home stretch of the season when it truly counts. Your body needs time to rest and taking days off to recover after a week or two of training will benefit you in the long run.When it comes to summer training, speed workouts aren't going to benefit you as much as the quantity of miles. Not saying that running 9-minute miles for 18 miles will help you reach your goals, but in the same sense, doing only 400m intervals won't benefit in the 5k as much as a quality 8-mile run.
During the few months of summer training, the idea is to build endurance and stamina, that will later coincide with speed and ability, personal and/or team goals. Finally, be prepared rather than burned out for the season ahead. Cross country is a difficult sport that takes a lot of time, energy, and dedication to succeed.
