Half Marathon and Marathon Trail Run Training Plans

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three trail runners on the trail

It's The Event every runner eventually wonders about. Could I? Should I? If your answer is "yes," then you'll need a training plan for your first trail marathon. The same is true for your first half marathon, which is both an interim step and a worthy goal in and of itself.

Below is a training primer for a half marathon or marathon event. You can find a wide range of plans and approaches out there, but all plans typically have a mix of the following:

  • An initial physical assessment
  • A variety of running tempos and terrains
  • Dynamic warm-up, along with post-workout cooldown and stretching
  • Gradually building up mileage until you're at or near your event distance
  • Nutrition and hydration planning

Your Initial Physical Assessment

a trail runner with heart rate monitor watch on

Let's assume you have at least a moderate level of physical conditioning. Ideally, you have completed a 5K or 10K trail run recently, or perhaps run a half marathon or more in a road event. Going from the couch to a half marathon on the trail isn't recommended.

Your first step, as it is with any new training program, is to consult your physician. After that, you can train solo, but taking some classes, joining a running club and/or finding a coach or trainer is always a good idea and makes training more fun.

Find a Running Class or Club at REI

You can also get technique help from trail-running classes and clubs:

Find Your Class

Monitoring Your Heart Rate: You can train more efficiently if you wear a heart rate monitor. Each type of running you'll do is intended to be done at a particular heart rate. That number varies with your age and fitness, among other variables. To learn more, including how to calculate maximum heart rate (HRmax), read Heart Rate Monitors: How to Choose and Use.

If you're not interested in getting that scientific with your training just yet, we also offer an alternative way to guesstimate heart rates for each training pace, the talk test:

Run type

Percent of HRmax

How to estimate it

Easy run


You can carry on a conversation

Long run


You can speak sentences

Tempo run


You can speak single words

Speed run


You can't speak comfortably

Half Marathon and Marathon Training Schedules

For a comprehensive approach to your training, you can simply follow one of these calendars:

12-Week Program for a Half Marathon Trail Run

training plan table for half marathon trail running race

16-Week Program for a Marathon Trail Run

training plan table for marathon trail running race

Half Marathon Printer-friendly version (PDF)

Marathon Printer-friendly version (PDF)

You can also use our training calendar as a starting point, then modify it based on your experience and needs. Regardless of the calendar you choose, your weeks should start easy, gradually become harder and then become easier the week prior to your event.

Pre- and Post-Run Routines

Each type of run (except easy runs), along with hill work, should be bookended by the following routines. See the related article list at the bottom of this page for specific exercise suggestions and details about how those exercises should be done.

  • Dynamic warm-up: activities like skipping, lateral shuffles, high knee exercises and butt kicks can all be effective at warming up muscles through a range of movement. Spend at least 5 minutes before each run doing these.
  • Cooldown: Spend at least 5 minutes after your running session jogging slowly, then walking.
  • Stretching: Spend 5 to 10 minutes after your cooldown doing static stretches. Concentrate on your biggest and least flexible muscles. Yoga poses and foam rolling during this time can also improve flexibility and recovery.

Mileage Totals

Whether your event is 13.1 miles or 26.2 miles, you have to build up the endurance to run that far. These training schedules increase weekly mileage totals, and will have you running within 10-15 percent of your race mileage on your long run. You don't need to actually run your full event distance beforehand, nor do you need to tally weekly miles. If you follow the plan for your event, you'll rack up the miles you need.

Types of Run Paces

Your body is efficient at adapting to doing the same thing repeatedly—like running a particular distance on a particular course. In order to improve, you need a variety of paces. Each pace engages a different energy system, which in turn provides benefits ranging from improved efficiency and running mechanics to better cardiovascular conditioning.

Varying your training paces also mimics trail-running conditions, because terrain and elevation changes require you to constantly adapt your running pace. Our plans include the following running paces:

running icon

Easy run: The goal is to stay active as you build your cardiovascular base. Easy runs are the foundation of any good training program. Slip in a run between your other responsibilities. Make it social to help you stay motivated.

tempo icon

Tempo run: Tempo runs improve metabolic efficiency, making it easier to run at a faster pace before your muscles fatigue.

speed run icon

Speed run: Speed runs improve cardiovascular conditioning and heart and lung strength. Your body learns to run at a fast pace more easily, making you a more efficient runner.

long run icon

Long run: These runs stretch the limits of your base miles and develop your aerobic endurance. Get out and explore new trails and focus on honing your running mechanics rather than racing. You'll increase mileage on these runs throughout your training calendar, running almost as far as your event's distance shortly before the big day.

hill icon

Hills: Developing the skills, strength and endurance for climbing and descending is critical for trail-running events. Research your event's elevation profile ahead of time. Then select training trails that match the steepness and length of the hilly sections on your event course.

Non-Running Days

active heart icon

Active rest: Do any activity that keeps your body and muscles moving without taxing your cardiovascular fitness or recovery process. That includes activities like light walking, passive yoga poses or a stretching/foam-rolling session. You can also do cross-training to build strength. Active rest days help prevent soreness and reduce the likelihood of injury.

heart icon

Rest: The goal on these days is to give your body a break. Rest days are critical to avoid overuse injuries.

Your Nutrition and Hydration Plan

Being short of fuel and fluid is bad for any event. For a half or full marathon, though, you invite the dreaded "bonk," where you're reduced to a shuffle or are forced to stop altogether. Thus planning and perfecting your approach to eating and drinking is central to your overall training. Use your long-run days as trial runs for that plan.

In addition to figuring out how much fuel and fluid you need, your plan has to reflect foods and drinks you've consumed—and kept down—during long runs.

Related: Trail Running Nutrition Basics
Understanding the basics of nutrition for trail running can help you run longer and feel better. This article covers the basics of exercise nutrition, what to eat and when to eat it, and nutrition tips for trail running.

Read the article

Related: Trail Running Hydration Basics
To feel your best while running, it's important to stay well hydrated. Learn how much to drink and how to avoid dehydration and over-hydration.

Read the article

Research your event ahead of time to figure out nutrition and hydration logistics. Aid stations can be part of your plan. Because many trail runs are open to the public during the event, you should also consider setting up a support team with resupplies ahead of time. Or you can simply carry everything yourself. Read Trail Running Gear Systems to learn about carrying options.


trail runner with compression sleeve on leg

Trying to push through injury is a common mistake. The result is inevitably more damage and having to abandon training altogether until you're completely healed.

A Long Training Calendar Is Hard on Your Body

Because you train for more weeks and run more miles, vigilance is even more important during half-marathon and marathon training than it is for 5K or 10K training. Be on the lookout for the first sign of injury. Catch it early and you might be able to take a day or two off and heal adequately (check with your doctor if you're unsure). When you resume, start with an easy day.

Pay Attention to Pain Location

The difference between soreness and injury is usually signaled by pain that's concentrated in a single place or on just one side of your muscle. If the calves of both legs are uniformly sore, that's probably a sign that the training has gotten serious, not that you're seriously injured, but again, consult with your doctor if you're in doubt.

Rest Is Key

We encourage you to adapt our calendar to your needs, but we don't recommend replacing rest days or active rest days with running days. Overdoing running in your plan will increase your chances of developing repetitive strain injuries.

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