The case for the in-between day

Whether you’re preparing for a 5K or a marathon, you probably follow a training model that includes a couple of challenging workouts alternated with easy mileage days, a long run and a recovery day. This hard day/easy day training paradigm has become very popular over the last few decades, and for good reason — it’s effective. But is it the only way to train? There is a whole range of intensity between easy and hard, and are we missing out on some benefits by never venturing into that training zone? In-between days are a great tool to help you get more out of your hard days, and may give you the extra push you need to snag your next PB.

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What does an in-between day look like?

An in-between day doesn’t mean taking your entire easy run at a faster pace. Instead, it means adding some harder elements into your easy day to up the intensity a little without making it a full-blown hard day and inducing fatigue. This could include adding some short accelerations at max speed and some plyometric exercises after your run, doing some quick post-run hill sprints or doing some 30-second surges in the middle of your run.

In-between days like this can serve more than one purpose, including priming your body for the next day’s hard session. Steady, slow mileage can sometimes make your legs feel sluggish, so injecting some speed in the middle or at the end of your run can wake them up a bit before the next day’s intervals. Secondly, in the hard/easy model we tend to cram as much work as we can into our hard days, so an in-between day takes some of that load off and can actually allow you to do slightly more work over the course of the week without really noticing. This, in turn, can lead to training adaptations that you may not get otherwise.

Elite performance coach and writer behind thescienceofrunning.com, Steve Magness, uses this approach when coaching some of his athletes (Magness has coached several Olympic and World Championship runners).

” The key to these in-between workouts is doing just enough so that we get a training stimulus, but not so much that it became a hard day’s work and fatigue is created,” he explains on his website. “By getting away from the polarized hard and easy paradigm, you might just be able to take your performance to another level without adding any more grueling workouts to the program.”

So… are easy days out?

Definitely not. There are still many benefits to easy days, and there is a reason you should keep them easy. Training adaptations don’t happen when you’re cranking out hard intervals around the track — they happen as your body recovers. If you go too hard all the time, you’ll never reap the benefits of your hard work and ultimately end up burnt out and injured.

If you choose to use this training model, you should do so with caution because it is easy to do too much and overtrain. If you are an experienced runner who is looking for an additional training stimulus, you could start by adding one in-between day into your program per week, and see how your body reacts. Just remember to listen to your body, and if you’re feeling particularly beat-up on an in-between day, you may be better off using it as an easy run or taking the day off altogether. Additionally, if you’re still very new to running, a training schedule that involves easy days, in-between days, hard days and a long run day is likely too much. Instead, just focus on having a consistent running schedule and building up your mileage slowly.

Finally, remember that slow running is also important to performance because it trains your aerobic system and slow-twitch muscle fibres, and teaches your body how to burn fat more efficiently as a fuel source. All of these are important for success in distance running, which is why your easy days are still a valuable and necessary part of your training. This is also why even on an in-between day, the majority of your mileage should be done at an easy pace.

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