For The RepsBlog

Running

Trail Half Marathon Build

Trail half marathon plan with vert and durability focus. 14 weeks, five runs a week.

Runner on a rainy forest trail with ferns
Runner on a rainy forest trail with ferns. AI-generated image.
Distance
Half marathon
Length
14 weeks
Runs per week
5
Level
Intermediate
Goal
Finish

Who it's for

You already run a few times a week. It is built to get you to the finish of a half marathon in good shape.

Hill work is built in for a hilly course.

It is made for trails, not the road.

How the weeks work

It runs for 14 weeks with five runs in each.

If life gets in the way you can stretch it to 18 weeks, or tighten it to 12 if you are already fit.

The last 10 days are a taper: less running, a little intensity, so you start the race fresh.

  • Hill repeats: run up at a strong effort, jog back down, repeat.
  • One long run a week that grows slowly. Run it easy; the time on your feet is the point.
  • Threshold runs of 15 to 30 minutes at a comfortably hard pace. You could say a few words, not hold a conversation.

Setting your paces

Start with a 10K time trial. Your result sets the paces for the rest of the plan, so run it honestly and on fresh legs.

Making it stick

  • Keep easy days slow. Most plateaus come from running them too fast.
  • Put an easy day or a rest day after every hard session.
  • If you miss a week, pick up where you left off instead of cramming the sessions in.