100k Ultramarathon Training Plan

Have you signed up to run your first 100k ultramarathon? Have you completed a few 100k races before and now are looking to follow a structured training plan on your way to the next finish line? The 100k is a unique distance, and some of the most popular ultras in the world are set at this distance, such as Ultra-Trail Australia (UTA), Miwok 100k, Bandera 100k, and more! For many ultramarathon runners, the 100k is one more stepping stone on their way to finishing their first 100-miler. If you’ve completed a few 50k or 50-mile races, then you should be adequately prepared for our 100k ultramarathon training plan.

Are You Ready to Train for a 100k Ultramarathon?

Much like our 50k and 50-mile training plans, before you take on a 100k training plan and race, runners should have a few years of experience with consistent running and racing at least at the marathon or 50k distance. An individual new to running could complete a 100k ultramarathon, but remember this race distance takes months to build endurance. We want to help you prepare for a 100k Ultramarathon while reducing the chance of overuse injuries or burnout. So it is in our best recommendation to be a bit more experienced as a runner.

You should be able to comfortably run at least 35-40 miles per week for 3 to 4 weeks in a row. Our 100k ultramarathon running plan starts at 32 miles in the first week and builds weekly mileage from there. You will be doing long miles almost every weekend to prepare both physically and mentally for your goal race. If you’re not quite there with your weekly mileage, that’s okay! We suggest focusing on your base building mileage. You may also use one of our marathon training plans, or the 50k training plan to help you train up to the 100k ultra-distance.

What to Expect:

Our 100k Ultramarathon training plan is 24-weeks in duration and focuses primarily on helping you get to the finish line of your race. This running plan is very similar to our 50-mile ultramarathon training plan. The one exception is that the total weekly mileage increases slightly more in weeks 14 through 18.

We use training cycles of three weeks hard, one week easy to allow for recovery and help prevent overuse injuries or burnout. Three weeks hard followed by a recovery week provide physical and mental adaptation to training stresses for a 100k race. You may find that you need to work in shorter or longer training cycles, and we address that in our “Modifying the Running Plan” section in this 100k training guide.

We layout the distances you should be running and give you a general outline of what you should be doing. Precisely what you do will depend largely on your level of running experience and running goals. We do not directly address course profiles. For example, is your race flat or hilly? Technical? Hot or cold? These are critical aspects of ultrarunning that you need to consider throughout your training to be best prepared for race day. In general, most of your 100k training should be on terrain and in conditions similar to what you will face on race day.

At a Glance:

  • Length: 24 weeks
  • Typical Week: 5 days of running and 2 days of rest
  • Weekly Mileage: 28 to 70 Miles
  • Optional Work: Cross-Training, Strength Training, Hill Work, Speed or Tempo Work
  • Longest Workout: 35 Miles
Download 100k Running Plan

100k Ultramarathon Running Plan Preview:

The following is a snapshot of what to expect in your free 100k Ultramarathon Training Plan download. The full download is a training guide covering not only the week-to-week details but also important training topics such as:

  • Properly increasing your weekly mileage and increasing your long-run mileage.
  • How to schedule and manage back-to-back long run weekends.
  • Using walking breaks to manage fatigue and overall running pace.
  • Midweek training, including cross-training, strength training, and rest days.
  • How to include speedwork or hill training, if desired or needed.
  • How to properly make modifications to the running plan.
The following training plan is designed for educational purposes and is not prescribed for any particular individual. The training plan preview presented above does not include complete details for what should be done on each training day. Consult your physician or other health care professional before starting this or any other fitness program to determine if it is right for your needs or if there are any individual health concerns to be aware of.

100k Running Plan Terminology:

WARM-UP: Run/Walk for 5 to 10 minutes at an easy effort before every workout (run days and cross-training days). A proper warm-up will help to gradually increase heart rate, improve circulation, loosen up muscles, and prepare you for the day’s workout.

COOL-DOWN: Run/Walk for 5 to 10 minutes at an easy effort after every workout (run days and cross-training days). A proper cool-down will help gradually bring your heart rate and breathing back down to normal levels after the day’s workout.

HEART RATE: If you have access to a heart rate monitor, then use this device to stay in the correct range and intensity level shown in the training schedule for a given day.

PERCEIVED RATE OF EFFORT (PRE): A way to rate your effort level based on your feelings about the level of intensity on a scale of 1 to 10. A 1 is considered ‘At Rest,’ and a 10 is considered “An All-Out Effort.” Use this scale in combination with Pace and Heart Rate to stay in the correct intensity level shown in the training schedule for a given day.

WALKING/HIKING: Walking should be 100% expected during your ultramarathon race. Practicing walking/hiking in training can be helpful to simulate what you will experience on race day. During an ultramarathon, we recommend at least walking out of each aid station. This strategy gives you a good time to hydrate, consume calories, and refocus your thoughts on the challenge still left ahead. To incorporate walking into your 100k Ultramarathon Training Plan, try to develop some rhythm between run and walk. For example, walk for 1-minute out of every 10 minutes or only walk when you need to drink water or take an energy gel. Walking breaks can help you regain control of your breathing, heart rate, and mental focus to know that you can accomplish this goal.

FLEXIBILITY: Stretch lightly after every warm-up and cool-down period. Stretching will help improve flexibility, increase circulation, speed up recovery, and reduce the risk of injury.

EASY EFFORT: Easy pace/effort is considered at or slightly above what you can maintain a conversation, 50-70% of maximum heart rate, and 2-4 on the Perceived Effort scale.

MODERATE EFFORT: Moderate pace/effort is where you can hear your breathing, but you are not breathing hard, 70-80% of maximum heart rate, and 4-7 on the Perceived Effort scale.

LONG RUNS: The key to ultramarathon training is the long run, progressively increasing in the distance throughout the 100k training plan. The long-run is done at a pace/effort that you can easily maintain a conversation throughout the run. Work on running with an even pace/effort from start to finish of the long run. Your long runs are the perfect chance to practice nutrition, hydration, and gear that you will use during your race(s).

BACK-TO-BACK LONG RUNS: Weekends of back-to-back long runs are done to simulate and adapt to running on fatigued legs and a tired mind. This type of long run structure can be an effective and safer way to increase total training volume without putting in extremely long runs every weekend. However, it would be best if you did not attempt to do back-to-back long runs every weekend, which will significantly reduce your time for recovery.

RACING: Consider adding a Marathon Race in Week 15 and/or a 50k Race in Week 17. These two races will allow you to familiarize yourself more with running in a structured event. If you do choose to race either of these weeks, DO NOT race it all out. If you can’t find a race during this week, feel free to modify the schedule around what races are available.

REST DAYS: Rest days are an essential component of training for any long-distance running event, especially a 100k ultramarathon. It is during your rest days that your muscles regenerate and get stronger. We designate Mondays and Fridays as days of rest for ultramarathon runners, which allows you to gather strength for the long Saturday/Sunday runs. Use rest days to get things done on your schedule, so you don’t lose sight of your training plan as the week progresses.

SPEEDWORK: There is no speedwork involved in the 100k ultramarathon training plan. If you feel you need speedwork to improve your ability or previous ultramarathon times, then we recommend using the second or third midweek run (Day 3 or 4) for such work. We recommend beginning each 100k Ultramarathon Running Plan focusing only on base building for the first 4 weeks. After week 4, you can start to progressively add 12 to 30 minutes of speedwork one day per week. The amount and type of speedwork are entirely up to you. Every 4 to 6 weeks, have a week with no speedwork to allow for extra recovery and adaptation to training.

HILL WORK: There is no hill work involved in the 100k Running Plan. If your ultramarathon race calls for large amounts of vertical gain or loss, then we recommend purposefully scheduling in runs on similar elevation profiles as your chosen race. Depending on where you live, completing hill work can be pretty challenging. Be creative with the use of parking garages, treadmills, stairs, etc.! You can complete 1 day per week of hill training. Consider alternating weeks if also incorporating speedwork. Also, if your ultramarathon race features a significant amount of elevation change, consider completing long runs on hills as well.

CROSS-TRAINING: Include activities other than running and walking in your training plan. If you are entirely new to exercise, you may want to wait until weeks 4 or 5 to add cross-training workouts. If you are already active 3 to 4 days per week, start the cross-training 1 to 2 times per week. Examples of activities for cross-training may include cycling, elliptical, rowing, stand-up paddling boarding, swimming, or yoga. Cross-training will help to reduce the impact on your body and reduce the risk of injury from running. Cross-training can also speed up recovery time between running workouts. Cross-training activities should remain low impact and low intensity. If you are ever feeling too fatigued or sore from running, then you may want to consider taking an occasional cross-training day as an extra day of rest.

STRENGTH TRAINING: A form of cross-training, strength training can be a great way to increase lean muscle and boost metabolism while at rest. Strength training can be completed using bodyweight, free weights, resistance bands, weight machines, or Pilates, Yoga, or Cross-Fit classes. Include exercises for the upper body, core, back, and lower body. Warm-up with a run/walk for 5 to 10 minutes. If you are new to strength training, start with 1 set of each exercise for 12-15 repetitions. The goal is to work your muscles to fatigue or until you can no longer maintain proper form during the exercise. Continue with 1 set of each exercise for weeks 1 through 3, then progress gradually over a few weeks to 2-4 sets of each exercise for 8-15 repetitions.

MODIFYING THE PLAN: Don’t be afraid to move the workouts from day to day during the week (Days 1 to 5) but try to maintain the weekend schedule (Days 6 and 7) as much as possible. You may find that this does not always match up with your friends or running group’s agenda. However, these long run efforts have been structured in a way to prepare you for an ultramarathon best. For example, switching the order of Day 6 and 7 in a week with back-to-back long runs will not result in the same training effect and preparedness for race day. Be consistent with your training, listen to your body, and progress as your fitness allows you to progress. At the same time, remember that training for an ultramarathon is a different type of long-distance running challenge that takes an extra level of dedication to achieve. Making too many modifications will result in not following the training plan and potentially not achieving your goals.

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