Interval training affects efficiency


I’m curious to know if interval training i.e. The Galloway method, negatively affects efficiency metrics?


I’m assuming the simple answer is yes, the run scribe efficiency metrics will be lower.

But like most things with running, I’m also assuming it’s far more complicated than it initially appears.

Here’s a hypothetical scenario:

Two identical runners with the same gait etc., complete the same 5k race with the exact same finish times. Runner A goes the same pace the whole time, while Runner B uses an “interval approach” (go hard, recover, hard . . . or the Galloway run-walk-run). Wouldn’t runner A likely have more “air time” over the course of the race, and thus higher efficiency metrics than Runner B?

Even if Runner B “race walks” during the recovery periods at a relatively fast walking pace, the higher ground contact time while walking would translate into less “efficiency” in the sense that this would reduce the overall time Runner B spent in the air while covering the 5k distance and thus the efficiency.

This is why it I imagine that it would feel much harder ( and much less efficient) to walk a 5k in under 30 minutes as opposed to running it. And this is why elites have such high flight ratios, e.g. see their post on Elites vs. Mortals: because it maximizes their efficiency.

And perhaps this also gets into that old debate about why you don’t see elite marathoners running their PRs with an interval tactic. It’s more efficient if they just stick to a mostly consistent pace with slightly negative splits (and mostly consistent “air time”) than not.



Brilliant. Thank you. Easy to understand when I step away from the sometimes difficult to understand and view from an illustrative and simple approach. I guess my next step is to run without intervals and see. I was slightly apprehensive as I do feel as though interval training helps prevent injury but…


No problem. But again, I could be wrong here, hence all my question marks. Maybe someone else with more knowledge about this stuff can chime in too.

My understanding is limited to what I’ve read on the Runscribe website and a book called Anatomy for Runners by Jay Dicharry, which I highly recommend (the best book on preventing running injuries that I’ve encountered, and definitely the best $12 I’ve spent on running).

If I correctly recall what I read in that book, the efficiency issue gets tricky because very short stance times (which correlate with more flight time and usually faster cadences) can also become less efficient at some point because they require more fast-twitch muscles and because you don’t get as much of a “rebound” or “slingshot” effect from the elastic energy stored and transferred through each stride. I’m not sure if and/or how Runscribe efficiency metrics would take this into account.

It’s also my understanding that higher efficiency (in terms of less ground contact time, more flight time) can also correlate with higher impact forces.

So all that to say: yeah, you could definitely experiment with it on different runs of the same length/pace. Your Runscribe might suggest that one run with a consistent pace was more “efficient” but involved more “shock,” while the other may have involved lower efficiency readings but less shock.

But overall, if the Galloway / interval style of running is keeping you healthy and moving from point A to B, then I wouldn’t worry about having lower efficiency metrics.