How to Follow a Training Program for a Marathon or Half Marathon, Even When Nothing Is Going Right

When you’re training for a race, a good training plan is key. With a plan, you’ll have all your runs planned out for you, with just the right mix of long runs, speed work, and easy mileage to get you to the start line strong and ready. But what do you do when the plan doesn’t match up with your life? You get sick and miss a week, or you realize too late you started on the wrong date. Or the plan calls for something you just can’t make happen on schedule, like a tune-up race. 

“What do I do???” I hear you wailing. Well, don’t worry. I’ll tell you what you do: you do your best to follow the plan, without letting any feelings of guilt or nervousness take over. Missed workouts are in the past, and you’ll move on without trying to make them up. For the most part, anyway. Let’s look at a few scenarios where you might have questions. But first—let’s zoom out so we can see the big picture.

Understand what your training plan is trying to do

Before we can talk about whether to do this or that run off-schedule, we need to get our bearings and understand what each part of the training plan is trying to do. I’m going to describe the phases in a typical marathon training program, and they apply to most hard training programs, including those for half marathons. There are a few different phases over the course of what’s usually a 12- to 18-week plan, and they’re laid out something like this:

The beginning

What it is: Several weeks where you run a similar number of miles per week to what you were used to doing before you started this program. During this on-ramp phase, the program will challenge you to keep a consistent training routine, and add some extra distance to your long runs and perhaps some extra speed work or strength training that you had previously been neglecting. This may or may not feel like its own phase; it may just be the beginning of the build. 

How you’ll feel: You’ll feel pretty good during this phase.

Your biggest priority in this phase: Sticking to the program and preparing for the work to come.

The build

What it is: A nice long stretch focused on building up your mileage, both in the long run and in total weekly mileage. This is the longest phase of the program, perhaps six to eight weeks long. 

How you’ll feel: You’ll experience some fatigue, sore muscles, and maybe some blisters or minor injuries—but these tend to be pretty mild and overall you’re feeling OK.

Your biggest priority in this phase: Keeping up with the increases and taking care of your body (good nutrition, shoes, etc.) so that you can stay healthy and keep training.

The peak

What it is: This is the three to four weeks or so when mileage is highest, workouts are hardest, and the fatigue is really starting to catch up with you. If it’s a marathon program, you’re probably doing some 18+ mile long runs. If your race is a half marathon or less, you’re probably doing long runs that are longer than your race. 

How you’ll feel: Somewhere between “pretty rough, but hanging in there” and “frankly, I feel like shit.” 

Your biggest priority in this phase: Surviving.

The taper

What it is: After all that hard work, you finally get a break. The long runs are suddenly a lot shorter, and you’ll find yourself running a lot less mileage than you were during the peak. This phase is often about three weeks long for a marathon, and one to two weeks for a half marathon. For shorter races it may be just a few easy days so you can rest up before race day.

How you’ll feel: Often this is when you feel the worst, because all of that fatigue has built up, but you haven’t had enough of a break yet to feel rested. It’s also very normal to go a little crazy as you start wondering whether your training was really good enough and whether you’re really ready for your race. But this is all part of the plan, and if you stick with it you’ll feel like a million bucks on race day. 

Your biggest priority in this phase: Recovery. Or to put it another way: following the damn program, and not giving in to the temptation to go run an extra 20-miler or a race-pace workout “just to be sure” that you can. 

General rules for modifying your training program when life intervenes

With those phases in mind, it becomes a lot easier to figure out what to do when something messes with your schedule. Here are some very general rules to follow in every phase:

• It’s OK to rearrange workouts. For example, if you can’t do your long run on Saturday, go ahead and move it to Friday or Sunday. 

• Prioritize your “key” workouts (long runs, speed work) and try not to miss those. If you have to miss a run for scheduling/life reasons, make it an easy run. 

• Don’t try to make up missed runs, especially if you were sick and/or had to miss multiple sessions. Pick up where you left off. And give yourself some grace those first few days back—take it easy and do what you can.

• Make sure the program ends on race day. The taper works genuine magic if you time it right, and the peak is what sets up the taper. Don’t mess with the timing of those last few weeks. 

• Nobody’s perfect. If you manage to do 90% of the program as written, you’re still on track and you’ll do great at the race.

Got it? Now let’s tackle some specific questions. These are all taken from running forums, subreddits, and coaches’ anecdotes about what questions they get most often. A coach or experienced friend is the best resource, since they know you and you can discuss the specifics of your situation, but if you’re just looking for general advice, here goes:

I started the program too early, and now I have extra time to fill. Should I repeat some of the weeks?

That depends on where you are in the program. Do not repeat weeks in the taper. That’s meant to be a short, sharp decrease in mileage. Stretching it out will rob it of its power. (Tapers are magic, I swear.) 

You also do not want to repeat hard weeks in the peak. Remember, that’s the highest fatigue part of the program, and you’re just trying to hang in there and not let it kill you. If the program is designed to have one 20-mile training run, it is foolishness to try to run two in a row. 

(There are, of course, exceptions to these rules. Some people might benefit from a longer taper, or have the fitness to do an extra long run and recover from it without too much trouble. But I’m trying to keep my advice general, and most people who say “fuck it, I’ll do an extra long run” will end up regretting it.)

So what can you do? I’d recommend these approaches, in this order of preference: 

1. Extend the beginning or build phases. You can certainly repeat week five of a 16-week program, no sweat. Feel free to make the repeated week(s) slightly different, maybe decreasing the long run by a mile or two, or doing hills instead of track repeats. Just try to keep it within the spirit of what that phase of training is trying to accomplish.

2. Add cutback weeks during the peak or late build phases. If you’re already in the peak phase when you notice your scheduling mishap, add an easy week in between some of the hard weeks. For example, the Level 3 Boston Marathon program has a 17-20 mile run in week 16, followed by 18-20 in week 17. You could insert a week in between where your long run is 13 miles or so, to give you a little bit of a break. Or say you’re following a Hal Higdon program that alternates between 20-mile and 12-mile long runs during the peak. Add an extra repeat of that cycle, maybe doing 16 or 18 rather than another 20-miler (since multiple 20’s is a lot), and following it with a 12 according to the pattern.

When in doubt, make the added week easier than the weeks before and after it. Your body will appreciate the extra recovery.

What if I don’t have a “tune-up race” to run? 

Some training plans will throw in a race partway through the program. A marathon program might have you race a half marathon in the middle of your training. A half marathon might have you race a 10K. 

Ideally this will be an actual race. You’ll sign up for the My Town 10K and have to figure out all your race day logistics: how early to wake up, what to eat, whether you want to carry your phone, and so on. You’ll also have the pressure of a timed course (no free pauses for water breaks) and the adrenaline rush of a crowd cheering you on. 

Having to deal with all that bullshit is half the point of doing a tune-up race. The other half is getting a chance to see how fast you can really run, and then you can use that result to help you decide what pace to target for your big race. (Plug in your race time here to see your predicted times at other distances.)

But maybe there isn’t a 10K in your town that weekend. Here are, in my opinion, your best options: 

1. Find a race of the correct (or similar) distance on a different weekend. Usually this isn’t a part of the training program where the timing is super critical. If you can get the full race day experience a week or two earlier or later, go ahead and swap things around to make that happen.

2. Run a time trial. This is just a race that you do on your own. There won’t be a crowd or a bib pickup table, but you can still test your fitness over the programmed distance. Reward yourself with a stale post-race bagel for verisimilitude.

3. Just do a regular long run. Usually the tune-up race takes the place of your weekend long run. Look at the weeks before and after it on the calendar, and ask yourself “if there wasn’t a race here, what would it be instead?” Make your best guess, and then do that. 

What if I have 12 miles programmed, but I really want to race a 5K or join a friend for a short run that day? 

This is the opposite of the dilemma above. There isn’t a race scheduled, but you want to do one anyway. Or some other scenario where you’ll be running, but not hitting the programmed distance.

The simplest answer is just: run a loooong warmup and cooldown. Three real easy miles before the 5K shouldn’t ruin the race for you; in fact, you’ll probably feel nicely warmed up by the time you get to the start line. And then you can do the other six miles as an extended cooldown. 

Same idea if you’re meeting a friend for a run. If they want to do a nice easy five-miler, you can do seven before they show up, run your last five with them, and then go to brunch together. 

If the race is a longer one—say, a 10K—you can also just treat it as a tune-up race. Run it all-out, and don’t bother making up the mileage. Depending on where you are in the program, a race and a long run might be too much to recover from. 

You wouldn’t want to do this every week, but once or twice in your training plan isn’t the end of the world. 

I missed my longest run, and now it’s taper time! Should I squeeze in a 20-miler real quick? 

You know the answer to this one by now: no. The taper is for recovery. Also, my god, you have no idea how many people miss their last 20-miler and then do absolutely fine at their marathon. 

I ran all my long runs, but some of them went really badly. I think I can redo my last 16-miler, but do it better this time. How do I—

That’s the neat thing, you don’t.

What if I am a special snowflake and believe these rules don’t apply to me? 

Honestly: maybe you’re right.  A cookie-cutter program is not guaranteed to be perfect for everyone. Just promise me something: whatever “bad” decisions you make, learn from them. Maybe you think you’ll be fine with a shorter taper. If you truly want to test that hypothesis, shorten your taper! Keep notes. And then see how you do in the race. 

Just remember that this kind of self-experimentation works best if you do the program as written your first time around, and then tweak it when you run your next race. You’re learning how you respond to training, which is an incredibly valuable skill as you grow as an athlete.