12 Week Marathon Training Plan This plan is built for a minimally-moderately experienced runner who can handle 35-50 miles per week. This plan incorporates 5 days of running a week all on single runs with one day off a week and an optional cross training day. This runner is likely looking to take to step up their training volume and/or intensity to make further progress as a runner. This plan is designed to be 12 weeks of marathon specific training, it is advised to start this plan coming off ...