21 Week 100 Mile Training Plan

This is the plan I used to train for my second 100 mile race.

So you’ve run a race or two, maybe even three and now you are excited about (and secretly slightly scared of) the possibility of running a 100 miler. Let’s be honest, if you are reading this, you are most likely not one of those people who are going to be winning 100 mile events. (Although if you are one of those people, email me! I have many questions to ask!)

Realistically, you are probably fairly similar to me; you have run races of all distances, probably multiple times, with distances anywhere from a 5k, a 10k, a half marathon, a road marathon, a trail marathon, a 50k, all the way up to a 50 miler, maybe even a 100k, but you just have not quite yet taken the leap to 100 miles. You are probably also somewhere between a back of the packer to somewhere near the top end of the middle of the pack, maybe borderline back of the front of the pack, but you are most definitely not ‘elite’ or really even close. But that does not really matter to you. You probably do not have a running coach and you probably ‘want to figure it out on your own’ with some internet research to help get you pointed in the right direction. You have probably searched, “100 mile training plan” and come across a dozen plus articles with various plans and lessons learned, but you are looking for just the right plan for you.

I know you. I mean, I don’t know you, but I know you. Why? Because that’s me.

So why is this this plan any different than any other 100 mile plan?
The absolute honest truth is it’s not. It is as much the same as any other 100 mile plan. But at the same time, it is completely different. There’s an end goal, there’s just a few miles thrown in there to keep you honest, and there is a set amount of weeks to work backwards from the race. But just like every other 100 mile plan, in the end it is up to you to twist and rearrange the plan, set some basic ground rules for yourself, hold yourself accountable to whatever mileage you bargain with yourself and ultimately put it all together and make it work, for you.

Here’s how I tackled my second 100 miler.

The basis for this training plan was a mixture of extrapolating my prior 50k training plan, 50 miler training plan, through knowledge gleaned from my prior training schedules, and working backwards from race day to fit my schedule. I started this training from scratch. Well, not entire from couch scratch, but kind of. I had taken off the prior few months from running to rest and recharge and had only occasionally ran a few times a week just for fun, averaging 10-15 miles. But having a decent base, I was able to ramp up my individual run mileage and weekly mileage relatively quickly.

The training plan is based on total miles run (as opposed to time based) and my main goal was just to finish in the allotted time. (My secret goal A-goal was 26 hours, B-goal was 28 hours and C-goal was 30 hours.) There was not any steep punishing climbs that lasted for miles, just mostly lots of punishing quad-killing rollers totaling approximately 12,000 feet of vert in the race I was targeting (Kettle Moraine 100).

The goals and assumptions of this training plan were:

  • Long runs can be slow. Try not to break them up into two shorter runs, but sometimes that is the only way to hit the mileage.
  • It’s ok to walk/hike long runs as necessary. It is even ok to stop for a short break.
  • Long climbs and descents for elevation gain is a low factor since the race has mostly all short 150’-200’ climbs.
  • Run on trails when possible. Try to hit at least a portion of a trail on every run.
  • Break up the plan into 5 training blocks, alternating between volume and speed.
  • Within each training block, break up the plan to 3 consecutive weeks of volume or speed and 1 week of recovery.
  • Stay healthy. It is ok to skip or shuffle training runs around each week.
  • Back to back weekend long runs are a staple to this plan.
  • One weekday slightly shorter long run is a staple to this plan.
  • Planned rest days are the days immediately following back to backs (For this plan, it fell on Mondays and Fridays).
  • Incorporate a few races as glorified training runs into the training plan for race day experimenting and practice.

For the most part I hit all my weekly mileage goals, sometimes exceeding and sometimes falling short and sometimes falling appallingly short and every so often blowing far past what was planned (because for no reason at all the thought of running a 100+ mile training week was oddly thrilling to me.) I somehow managed to follow all of my goals and assumptions of the plan. Although, I did not adhere as strictly to the tempo/threshold workouts as scheduled. This was obviously not a deal breaker to my race (I did finish!) however, who knows if the periodic speed work/faster leg turnover would have provided me the opportunity and edge to finish with a faster time or left me on the brink of an injury and over fatigued teetering on not finishing the race. Ultimately, I made a plan and I held myself accountable to follow it as best I could. That’s the real crux of a 100 mile race. The actual racing part is just gravy to the whole experience – the yummy, tasty kind of gravy that shows itself in the rewarded form of a belt buckle.

A few last things: Just to be clear, you are not going to win any race with this training plan. Remember a plan is just a plan and it should be broke, bent, altered, chopped and revised as required to avoid injury and fit around your life schedule.

Most importantly remember to have fun, because in the end, it is only running.

TT50 - 21 Week 100 Mile Training Plan

6 thoughts on “21 Week 100 Mile Training Plan

  1. Thank you for sharing your knowledge and experience.

    Thinking about doing 100 miles in Michigan in May 2020.

    Great and encouraging profile picture!

    Liked by 1 person

    1. You’re welcome and good luck if (when?) you do sign up! Which race are you looking at signing up for? Would love to hear your race report afterwards!


  2. Hi, I found your training plan online and looks good! I’m running the Centurion Thames Path 100 mile race in May 2020 so this plan will start for me early Next month! I’ve never followed a training plan but for this kind of distance I thought it would be wise. At the halfway point I’m thinking about swapping the back to back long run to 1 x 50 miler, to get the feel. What are your thoughts on this? Cheers! X


  3. Ah man, its so good to see a simple plan, written by someone who ‘knows me’ :)

    I dont suppose you have that in an excel or something? Save me typing it out, I’ll need to tweak to fit around family life.

    Liked by 1 person

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