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When we interviewed Adam Peterman in November, he described doing strides twice per week. That’s interesting, but expected. Strides are a near-universal element of road runner training, where the margins separating the best athletes are paper thin. So it makes sense that trail runners would be doing strides too. Arguing against the general usefulness of strides is like arguing that Everything Everywhere All At Once isn’t the best movie of 2022. People do it on Twitter, and they are wrong.
But here… there was a TWIST. Bum bum bummmmmmmm.
Adam described 8 x 20 second strides with just 40 seconds of easy running recovery. That’s a pretty narrow recovery window! The men that Missy Elliott does not want last longer than 40 seconds. It’s definitely not enough time to completely recover from a full-gas stride. Are we seeing a one-off phenomenon, or something with general takeaways for all runners?
I think that Adam’s approach to strides demonstrates a cool training wrinkle that I have somehow never written about after all of these years. What a perfect excuse to dig into a fascinating training element! Let’s get spicy, safely.
Training Theory Context of Strides
Mention short-rest strides to any training theory sicko, and the first thing they’ll think about will probably be “diagonals.” Common in many training camps in East Africa, diagonals consist of fast strides from one corner of an endzone to the opposite corner, with easy jog recoveries along the goal-line between each. Athletes will sometimes do diagonals for 30+ minutes, having it be a secondary workout focusing on speed endurance that has limited recovery cost.
Here’s where it gets wild and a bit creepy. Reports from the camps often say that the diagonals take just under 20 seconds, and the recoveries take just over 40 seconds. My co-coach Megan used diagonals as one of her primary workouts to win multiple trail national championships. Similarly, track pros who do fast straights with turn recoveries often approximate the 20:40 second ratio. Who does that remind you of? My god is that Adam Peterman music?!
In running and cycling, 30/30s have overlap too. The Uphill Athlete coaches describe introducing intensity via up to 30 minutes of 30/30s for advanced athletes, saying that “the 30 seconds is just long enough for the athlete to accelerate up to a high speed, hold it for 15–20 seconds, and then decelerate into the rest.” They say it improves high-end speed without significant metabolic cost, and cite that 30/30s are used by Kilian Jornet. I’d start fueling my runs with ivermectin if it was used by Kilian Jornet.
Physiologist Veronique Billat theorized that 30/30s maximize adaptations for velocity at VO2 max in runners, pioneered in a 2000 study in the European Journal of Applied Physiology. Theoretically, the session harnesses the principle that athletes stay at VO2 max for a few seconds after they stop running at VO2 max, so short-rest intervals optimize time spent at both fast speed and high aerobic demand. Cycling has adopted 30/30s, with top pros posting videos of these types of sessions. They may even share some evolutionary lineage with “Tabatas,” 20:10 second ratio intervals popularized after a 1996 study showed they had outsized benefits for some athletes (though see this article I wrote last year for an explanation of the time-horizon with Tabata intervals).
Running Strides: Research Context
While there aren’t studies comparing all of the different stride options applied over time, digging into the rationale behind doing short, fast intervals 30 seconds or less may provide some insights. Or it may not. But I brewed the green tea strong and I AM ROLLING WITH IT.
One of my all-time favorite studies was conducted in 2018 for Physiology Reports. It had 20 trained athletes complete a 40-day intervention with 10 speed sessions involving 5 to 10 x 30 seconds maximal running with 3.5 minutes of recovery between each, combined with a 36% reduction in weekly volume. Before and after the intervention, participants did a time-to-exhaustion test and two 10km tests (one with glycogen depletion) preceded by 2 x 6 minute intervals at 60% of VO2 max. Running economy improved by 2.1% in the 10k, and 1.7% in the intervals at 60% of VO2 max.
That is incredibly cool! Relatively short strides improved how the body used energy at much slower paces, a somewhat counterintuitive finding if you think it’s just about improving top-end speed, especially given that the study involved month+ reductions in aerobic volume. But what the researchers did next vaulted the study into the intellectual stratosphere.
The glycogen-depletion trials showed no performance change, which is weird. What could cause that? It’s impossible to know for sure, but the big leap in reasoning is that under depleted conditions, fast-twitch muscle fibers carry more of the load, similar to at the end of a marathon or ultra. Because the depletion tests showed no change, the authors theorized that the performance-enhancing changes from the strides happened in slow-twitch muscle fibers, which was backed up by the results of muscle biopsies showing positive changes in ST fiber protein expression.
It’s uncertain whether the results would be the same with shorter-rest strides. That study used a full recovery of 3.5 minutes. How would the body respond to a similar protocol, but with 20/40s or 30/30s?
My guess is that it may depend on the level of the athlete. Advanced athletes with efficient top-end output and aerobic systems to support it may see more benefits, in moderation, since ST fibers would be under higher load, plus there would be added aerobic capacity benefit. However, they’d need to keep reinforcing the aerobic system and maintaining true top-end output to see continued benefits. Beginner athletes may see initial jumps due to the VO2 max stimulus, but less benefit long-term due to the difficulty sustaining a high enough output to lead to the significant power adaptations in ST fibers. Or possibly there’s another driver altogether, and the correct answer lies somewhere else. Do your part and check between the couch cushions.
So the million-dollar question remains: why would you do short-rest strides when longer rest facilitates more efficient output? Based on who uses short-rest strides, and when they use it, my guess is that it’s optimal when the aerobic system and top-end output are both developed. In that formulation, they act as a bridge between aerobic development and speed development, reinforcing sustainable speed that will have more benefit for longer workouts and races, but without the risk of creating a lactate storm that undercuts aerobic growth.
The lactate-storm risk is a real one, though. In Billat’s 2000 study on 30/30s, the lactate levels of athletes doing 30/30s got to 6.8 mmol, which is relatively high, indicative of a Zone 5 stimulus (read this Norwegian training summary for a primer on lactate). Some of that is likely fine, especially for short durations. But too much of it risks undercutting aerobic development with excessive high intensity. That’s contrasted with normal strides with fuller recovery, where lactate levels do not have enough time to elevate substantially.
Let’s finish the article by breaking down the 3 components to think about in your own training, followed by a concluding paragraph featuring crab evolution (trust me, it will make 20% more sense than you might assume):
One: Short rest provides a natural governor on pushing too hard, reinforcing biomechanics of endurance running.
In coaching, I use short-rest strides more and more over time because it prevents advanced athletes from sprinting. Sprinting is not only risky for the musculoskeletal system, it could reduce the crossover to endurance running due to altered biomechanics.
Two: There is more stress on the aerobic and cardiovascular systems, but without the need for days of recovery like workouts.
Regular strides with 1-2+ minutes of recovery are all about mechanical output–increasing power with short stimuli that don’t activate anaerobic processes that could counteract aerobic development. Short-rest strides have that added velocity at VO2 max component, and could act as a bonus stimulus for the aerobic system any day of the week.
Three: Longer sessions act as a low-stress workout, shorter sessions are good for workout and race support.
With extended bouts of short-rest strides, athletes end up spending a ton of time at velocity at VO2 max or faster, but with limited recovery cost. Sessions over 10 minutes may be able to act as a secondary or tertiary weekly workout (though beware unwanted lactate storms). Meanwhile, adding 4-8 of these strides into an easy run isn’t too taxing and won’t have the lactate-storm risks, and they can likely be tossed into a week wherever you’d do regular strides.
Takeaways on Shorter Strides
The first priority for most athletes is to periodically add strides, starting on hills and only moving to flats if you’re healthy and resilient. But after you accrue those benefits and could do strides in your sleep, consider replacing some of your normal strides with 4-8 x 20/40s, a la Adam Petergod. If those go well, consider some 30/30s, while noting the risk of excessive high intensity lactate floods from the shorter recovery and longer intervals (we rarely use 30/30s for our athletes for that reason).
You can even do them uphill, or tack them on at the end of workouts like the track runners that do fast straights and jog turns after sessions. If all of that goes well, maybe do some longer short-rest stride workouts of 10-30 minutes as a supplement to normal training, or as the workout of the week if you’re within a base period or you’re stress-limited.
The most fun part of training theory is that a few million runners are trying different things all over the world, and sometimes there is convergent evolution where similar approaches evolve independently. Throughout training history, short-rest strides keep popping up, the crabs of the training theory world (a 2021 study in Bioessays found that the crab form evolved at least 5 separate times!). So consider giving short-rest strides a try, in moderation, especially if you’ve already exhausted most development from regular hill and flat strides. Harness that crab swag.
David Roche partners with runners of all abilities through his coaching service, Some Work, All Play. With Megan Roche, M.D., he hosts the Some Work, All Play podcast on running (and other things), and they answer training questions in a bonus podcast and newsletter on their Patreon page starting at $5 a month.