Expert Advice On How To Adjust Your Training Plan After Injury Or Illness

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Most runners will attest that their best performances and biggest improvements have come after extended chunks of consistent training. 

When you have long training blocks with no interruptions due to illness, injury, or otherwise, you can continually make gradual progress in the forward progression without losing any ground from time off.

However, as much as we’d all love never to be sick or hurt again, unfortunately, illnesses and injuries are somewhat inevitable at some point (well, maybe not injuries if you’re training smartly).

If you’re forced to take time off from running or working out, how do you get back to training when you’re feeling better? 

Jumping back into the workouts you were doing before you got injured or sick is likely too much for your body, depending on how long you were inactive. So, how should you adjust your training plan after time off to build back your fitness?

This guide will discuss how to adjust your training plan after time off due to injury or illness, looking specifically at how to return to training after a week off, a month off, and more.

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How To Adjust Your Training Plan After Time Off Due To Injury or Illness

Let’s get into the practical advice on how to adjust your training plan after time off due to injury or illness.

Although not hard and fast “rules,” the following guidelines can be used to help you determine how to get back to running after time off due to injury or illness:

If You Took 1-3 Days Off

If you took a day or two off, you shouldn’t need to adjust your training plan and be able to jump right back in, provided you feel back to 100%. 

You have not lost any fitness at this point; if anything, your body is a little better rested and ready to go.

However, if you had an illness with a fever, vomiting, or respiratory symptoms, you should listen to your body and expect yourself to feel somewhat weaker. 

You should wait at least 24 hours (ideally 48-72) after a fever breaks to go for a run. If you have vomiting and severe diarrhea, ensure you’ve hydrated aggressively with fluids and electrolytes before you try running.

If you’re feeling completely back to normal and just had a minor niggle or felt a little under the weather, you can resume your training plan exactly where you were.

If your return-to-running day falls on a hard workout, however, you might want to shift the workout a day or so and swap it with a distance run day; just go get your “sea legs” back under you.

A person laying on a couch, blowing their nose.

If You Took 4-7 Days Off

Generally speaking, if you took 4-7 days off from training due to injury or illness, you can resume your training plan where you left off, as with taking just a few days off.

Taking less than a week off from running will have no impact on your aerobic fitness (VO2 max) or your muscular strength and endurance. In other words, you’re just as fit as you were before you stopped training.

Heed the same advice regarding returning carefully after fevers, respiratory illnesses, and vomiting illnesses.

If You Took a Week to 10 Days Off

If you take a week or so off, it’s natural to start to worry that you’ve lost some fitness and won’t be in good shape anymore.

Rest assured, studies show that you don’t lose any fitness unless you’re sidelined for at least two weeks or so.

With that said, if you had an illness or injury that had you resting for 7-10 days, there’s a good chance that it was more than the mildest of sicknesses or pains, so you can expect that you might not be feeling your best the first run back.

Although taking 7-10 days off from training doesn’t in and of itself obligate you to adjust your training plan because your fitness hasn’t really declined, it’s usually a good idea to take your first 1-2 days back easier than you normally would.

Slow your pace or just run by effort and time rather than distance. Also, consider shortening the distance of your run. Don’t do a speed workout or long run—just stick with an easy base run.

Stop and walk if you feel tired or notice symptoms like dizziness, breathlessness, or pain. Focus on recovery by hydrating and getting a high-protein snack or a nutritious meal.

Try again the next day, meeting your body where it is.

A person holding their ankle.

If You Took 2 Weeks Off

Once you hit roughly the 2-week mark in terms of time off from running, you’re starting to venture into territory where some amount of aerobic fitness has been lost.

Studies show that after about two weeks of inactivity, you lose about 5-7 percent of your VO2 max

This isn’t necessarily a ton, but it can affect how you feel when running. Your heart rate and respiration rate will be higher than previously at similar submaximal paces.

As a result, you’ll need to adjust your training plan after two weeks off.

Take a full week to get back up to speed, literally and figuratively. You may even need a full two weeks, depending on the reason why you took time off from running.

As a general rule of thumb, run about one to two minutes per mile (45-90 seconds per kilometer) slower than your usual pace.

Moreover, run about 50-75% of the distance or time you would have run before your time off, gradually increasing this percentage over the course of that first week back as tolerated. This will help prevent muscle soreness and get your legs accustomed to running again.

A person running on the side of the road over a bridge.

If You Took 3-4 Weeks Off

You start to lose aerobic fitness (VO2 max) fairly rapidly after two weeks, so by 3-4 weeks off from running, you can expect your VO2 max to drop by at least 7%.

Evidence suggests that detraining results in a rapid loss in maximal oxygen uptake (V̇O2max), blood volume, ventilatory efficiency, increased reliance on carbohydrate metabolism during exercise, lowered glycogen levels, reduced lactate threshold, decreased capillary density and oxidative enzyme activities in skeletal muscles, among changes in hormones.

Furthermore, evidence suggests that you start to lose muscular strength after three weeks of inactivity.

The muscles, tendons, ligaments, joints, and bones in your feet, legs, arms, and core will need to adjust back to the forces and stresses of running since some of the adaptations in these tissues are lost after 3-4 weeks of disuse.

When you’re thinking about how to adjust your training plan after time off due to injury or illness, it’s around this time—3-4 weeks off—that significant changes need to be made.

Expect it to take at least two weeks to get back up to your prior volume and intensity if you took three weeks off of exercise and three weeks to come back to full training after a month off.

Depending on your prior level of fitness and overall training plan, this may be slightly more conservative than it will end up being, but it’s a good rule of thumb to set reasonable and healthy expectations. 

Coming back too aggressively is likely to result in injury.

A close-up of running sneakers and someone taking a step.

If You Took 1-3 Months Off

After a month of rest due to injury or illness, you will have to essentially restart your training program by rebuilding your base.

One study looked at the effects of four weeks of inactivity (less than 2 hours per week of exercise) after an 18-week training program that culminated in the 2016 Boston Marathon in 21 male runners.

Of the most notable changes, subjects saw an average decline of 6% plasma volume, 8.1% left ventricular wall thickness, 10.3% loss of left ventricular mass, and an 8.2% loss in the right atrial area after four weeks of detraining. 

Another study demonstrated that VO2 max dropped to 16% below the initial value achieved during training after 8 weeks of inactivity. 

However, it stabilized, and no further appreciable losses in VO2 max were noted at the 12-week mark of inactivity.

Moreover, though VO2 max had dropped significantly (16%), it was still higher after 12 weeks of inactivity than it was in sedentary control subjects who had never trained. 

Therefore, though aerobic fitness drops quickly, losses in fitness slow after two months or so.

A person running down the road.

Decreases in VO2 max during detraining were attributed to decreases in stroke volume, plasma volume, and ventricular muscle fiber strength.

All this is to say after 1-3 months of time off due to illness or injury, expect to start back slowly. 

Take about 3 weeks for a month off and 4-5 weeks for 2 or 3 months off to regain your fitness and build back up to training. 

During the first week, just run every other day. Start running 2 days in a row on the second day, followed by a day off.

The first 2 weeks should be just base-building, aerobic runs. Run at least 1-2 minutes per mile slower than your previous pace, and keep the weekly volume to 50% or less of your lower weeks in your prior training schedule.

For example, if your previous training schedule averaged 30 miles per week and peaked at 45 miles per week, run no more than 15 miles per week for the first 2 weeks.

Then heed the 10% rule (don’t increase your mileage more than 10% from week to week) if you’re feeling tired or breathless on your runs. Otherwise, you can potentially scale up 15% or so.

In the third week, you can work back into fartleks, tempo runs, hills, and strides, gradually returning to your prior paces and intensities as tolerated.

A casted foot with crutches of a person who will need to adjust their training plan.

If You Took More Than 3 Months Off

At this point, congratulate yourself on returning to running but restart your training as if you are a beginner. 

Run no more than every other day as you start back, keeping your mileage low and effort level easy.

Above all, any time you’re trying to figure out how to adjust your training plan after illness or injury, make sure you are listening to your body and using your physical cues to gauge how much you can run and when you need to dial it back. 

Err on the side of caution, be patient, and enjoy the journey.

If you are looking for some guidance and training plans, check out our training plan resources.

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Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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