The balance of your training may not support runs much longer than this with attempts at longer distance leading to injury or extreme fatigue. For those with more experience, especially those trying to improve performance, a few runs up to and possibly beyond the marathon distance could be valuable. These can be incorporated into the training run by simply starting and finishing at a slower pace. Increased mileage makes a stretching program a necessity, especially for the muscles in the lower back and the entire back of the legs. A specific stretching program is described in the Supplemental Training Chapter.
Some runners like to break up their longer mileage workout days into two runs.
Endurance training benefits still are derived from this due to incomplete recovery between runs. However, the benefits are certainly not as great as from a single longer run. To assist you to devise a personal training program, several base building mileage progressions are given below. Remember to use the training pace charts given in the appendix to determine a target pace for your training runs. See pace charts in Appendix.