What Runners Should Do If You Missed Training

By Jason Koop,
Head Coach of CTS Ultrarunning,
author of “Training Essentials for Ultrarunning”

Athletes miss training sometimes. They get sick, something comes up at work, there’s a family emergency, or any of life’s innumerable curveball. Reducing the number of training session you miss goes a long way toward reaching new heights in fitness and performance. This type of consistency has been key to safely increasing training workload for some of the elite athletes I work with. If you do miss training occasionally, how you move and shift the subsequent days and your attitude surrounding your training can have a big impact on your success down the line. Here are some rules of the road (err, trail) for when you miss a day or three of training.

The science of detraining

I’d be remiss if I did not mention what a few days off does to fitness. Surely those missed days result in a monumental step back in the fitness you have so arduously earned, right? Here’s a summary of the research: if you miss up to 7 days of training, there are no meaningful fitness implications. Zero, zilch, nada. Sure, I can throw someone in our physiology lab and measure that components of their physiology like VO_{2 max} or stroke volume is down by 2.21% or some other meaningless amount (see the graph below). But, some minutia of physiological degradation does not always mean a performance degradation.

The practical amount of fitness degradation from missing up to a whole week of training isn’t much. This is especially true if you look at it through the lens of the entirety of training (see more on that below). Remember this when you get a cold or have a work trip and are trying to determine the timing of your first run back. Err on the conservative side, your fitness is likely not to be impacted at all.

Figure 1- Effect of training cessation on the physiological determinants of maximal oxygen uptake (VO2max). from Bosquet, Laurent & Mujika, I. (2012). Detraining.

So here’s my caveat for all of the moving and shaking of training to come. All of the scenarios below assume you are ACTUALLY ready to move on with training. If you are coming off of an injury or illness, you FIRST need to make sure you are ready to resume training. THEN, you can follow the steps below.

Rule #1, don’t panic

Nobody ever made a dime panicking, and your fitness will not improve if you panic about missing a day. I previously wrote that your longest long run represents a small fraction of the total run volume. Similarly, an unplanned rest day represents a very small part of the totality of training. Furthermore, the training run you missed does not evaporate into thin air. If you remember anything from this article, remember this:

‘Your body can only handle so much training stress over long periods of time.’

If you have been thoughtful about training or you are working with a coach, the training stress you missed during one day will (at least) partially make its way back into your running routine in some shape or form. You’ll be more recovered, meaning your next workout can be of higher quality and potentially ‘make up’ for the lost training session. You can also rearrange your schedule like in the examples below. In certain cases, both happen.

Missed training opportunities are rarely as big as they initially seem on paper because we are looking at them through a short term lens. Broaden that lens out several weeks and an occasional missed training session is not as big of a deal. The key is to have a long lens when evaluating training. So, look at your training over months not days.

If you missed one to two workouts

If you miss one or two days of training, my advice is simple: ‘play on’. Even if the two days you missed were ridiculously important, I honestly don’t think it’s worth making those days up. This is particularly true if you have been doing a good job being consistent with your training in previous weeks. In my experience, the extra recovery does most runners more good than the disruption or effort required to make up for missed training. And based on the science of detraining above, you won’t really skip a beat.

If you missed more than three days of training

If you missed more than three days of training, your best course of action is to rearrange between half and 75 percent of those missed days somewhere later down the line. You can do this by replacing an endurance day with a harder interval workout, adding time on to a shorter run, replacing a rest day and likely, all of the above. When I am doing this with my athletes, I take an ‘all of the above’ approach. By adding bits of training to certain days and substituting one workout for another, you can achieve close to the previous plan.

Don’t try to make up 100% of what was lost. And, don’t simply copy and paste the missed workouts down the line. Remember, you still need to recover from whatever monkey wrench life has thrown at you. So, you are not going to be able to make up 100% of what you lost (nor should you try). I also encourage athletes and our coaches to make scheduled changes quickly, even if you have to modify it again later. This demonstrates how the rest of the schedule changes over the next several weeks. As a result, it takes the pressure off the athlete to return to training immediately. They can see that the days are not completely lost, merely shifted around and modified.

Here’s a 4-point action plan:

1. Aim to replace 50-75% of the missed runs/volume over the course of 4-6 weeks
2. Look to replace the more important workouts first. This will normally be interval days
3. The total time of any missed endurance runs can be spread out over the course of several days. I would not increase one day by any more than 25% of what you had originally prescribed. For example, if you miss two different one-hour endurance runs (2 hours total) you can replace that volume over 4-5 different days in 15-minute increments.
4. Missed recovery runs do not need to be replaced

I’ve provided an example below to give you some guidance on this if it happens in your own training. In this example, 4 days were missed in the first week (indicated by the red X) from the training plan on the left. The new training plan is displayed on the right. I rearranged the harder Tempo workouts to subsequent weeks (indicated by the blue arrows on the left and green text on the right) and added 15 min to some of the subsequent long runs. Note that none of the hard workouts were missed, one hour of the two-hour long run was replaced by adding 15 minutes to four subsequent long runs and the recovery run was not replaced. In this way, some, but not all, of the four days of missed training is replaced by some smart rearrangement.