Q&A: Ok to split your long run?

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Welcome to another edition of Coach Carl Q&A (submit your questions here). Let’s get to it!




When work and family schedules are tight, can a mid/long run be broken into two workouts in one day? Can I run 5 miles at 6am and then run another 5 miles at 6pm or would that hurt my progress?
— Jim




This is a great question because for most of us, running isn’t going to be the number one priority in our schedules. So knowing when you can make adjustments and when to hold fast to the training plan is important.


There are a couple of factors at play when looking at this question …


The first is the idea that your body responds to the stimulus that it is given. That means that when you run for, say, 5 miles — your body goes through an adaptation process that makes you better at running for 5 miles. What it doesn’t do is assume that if you ran 5 miles this week that you’re going to want to run 6 or 7 or 10 miles next week.


your body responds to the stimulus that it is given

The second (and related) factor is that when it comes to training for the marathon, the long run is always going to be the most important training run of the week. When you’re getting ready to run for 26 miles, you body needs to build a lot of endurance.


What does that means in terms of Jim’s question?


Well, in a perfect world you would not split the long run up. There are things that happen in and to your body during a 10 mile run that just don’t in a 5 mile run, even if you do two in one day.


But in an imperfect world, what is the best course of action?


First, I think if the run is a distance that you have not run in training yet — i.e. it’s the first time that you’ll be running 14, 16, 18, whatever the distance — then you should do everything you can to not split the run up. The first time at a distance will be an important stimulus to your body to increase endurance, and will pay off for future long runs and the race itself.


the first time at a distance will be an important stimulus to your body


Second, if you DO split the long run, I would try make the first run longer than the second. So instead of 5/5, try to make 6/4 work with your schedule if possible.


A couple other caveats to consider:


1) If it is a recovery week in your training schedule, you can probably get away with doing less mileage than what is written on your plan and be ok. So, if you have 10 scheduled as a down week and only have time for 7, I wouldn’t necessarily worry about doing a second run — as long as you’re not cutting your long runs short every week.


2) If it’s not the first time you’ve done the distance, but it’s also not a recovery week per se — one of those “in the middle” weeks that marathon plans often include — then you can always consider doing a bit more mileage split into two runs to make up for splitting the run up. So for example, if you have 10 on the schedule instead of 6/4 like I suggested above, maybe you can find time to do 6/5 or even 7/5. It’s a bit of “extra credit” to make up for the fact that you’re not doing the mileage all at once, and since you are splitting the distance up, you have less cause for concern that you’re doing too many miles.


Bottom line is that when life gets in the way, there are certainly ways to adapt your training schedule to make your running fit in — but if you make it a habit to split up the long run, you will definitely not be as prepared for race day.


About Coach Carl
Coach Carl is a USA Track & Field Level 2 endurance coach who works with runners of all ability levels to reach their goals. He has been featured in Runner’s World, Women’s Health, Men’s Fitness, and Competitor. For information on his coaching services, click here.