Why And How To Run Strides To Improve Speed On The Trails

If you look at hundreds of elite athlete training logs, short, fast "strides" will be a close-to-universal element. There is variance in timing of strides, distribution throughout the year, speed and duration, but you'll rarely see an athlete exploring the top of their performance potential without them.

That's weird, right? How can running quickly for 30 seconds or less have much relevance for events from 30 minutes to 30 hours? The answer likely lies in how adaptation happens in the interaction between cells and systems of our muscles and bones and capillaries, applied via biomechanics and the nervous system.

A flow chart that diagrams adaptation would have thousands of arrows, and even then would be simplifying complex processes that often cannot be measured directly. In other words, adaptation is a lot like the lottery for entry into the Hardrock 100. For endurance runners thinking about their own training in an applied, practical sense, I like to break it down to four component parts that work in tandem: the aerobic system, the musculoskeletal system, the biomechanical system and the neuromuscular system.

Systems Overview

The aerobic system powers working muscles via the heart, lungs, and circulatory elements like capillaries. The musculoskeletal system absorbs and transmits power during activity. The biomechanical system describes the efficiency of that power absorption and transmission via movement patterns. And the neuromuscular system is how the brain and nervous system put it all together. Each of those elements has countless component parts, and each feeds back on one another over time.

The problem is that it's tempting to prioritize the aerobic system and musculoskeletal system above all else, using total effort or stress as a proxy for the value of training. That model views runners as "lungs with legs," and it risks missing some of the complex feedback cycles that fall between a breath of oxygen-rich air and running speed on a road or trail.

While there is no 100-percent proven reason that strides work, their importance is likely related to the complex interplay of those elements that go into long-term adaptation. Aerobically, short strides could improve cardiac output, but that benefit is likely minimal. Musculoskeletally, they stress output-per-stride, requiring muscles to maximize efficient power output. There are even theories that strides could positively alter protein expression in slow-twitch muscle fibers, and that underscores the idea that all of these adaptation processes likely have immensely complex explanations. Biomechanically and neuromuscularly, the mix of higher cadence, lower ground contact time, and maximized power could help optimize form and power transfer, along with complex pathways involved in how the brain makes it all possible. If I say "complex" one more time, I complete my punch card that entitles me to a free six-inch sub.

Feeding back development of max sustainable output via strides and similar efforts into normal sub-max training consisting of easy efforts and workouts can raise the ceiling on both. And that's how an athlete can have long-term breakthroughs to previously unthinkable levels.

To simplify it a bunch, an athlete usually will be within a certain percentage range of their short stride speed in longer events. That range is variable and based on a number of individual-specific factors (i.e. muscle fiber distribution, sex, athletic background) and my co-coach/wife Megan and I went into more details in our book and podcast. But the big takeaway is this: maximum sustainable output (sometimes called "speed endurance," though that term means many different things depending on where you look) is often loosely connected to sub-max sustainable output (velocity or power at lactate threshold or harder and aerobic threshold or easier).

Applied Studies

Many studies support the empirical framework seen in elite-athlete training. A 2018 study in Physiology Reports had 20 trained athletes do 10 sessions of 5 to 10 x 30 seconds fast in a 40-day training cycle where total training volume was reduced by 36 percent. After the intervention, 10K performance improved by 3.2 percent. Perhaps most interestingly, VO2 max didn't change at all (and it actually had a non-significant decrease). Instead, the athletes improved by two percent in their velocity at VO2 max.

In other words, their aerobic systems had not improved, they were just going faster with the oxygen they had. The progress was based in some combination of their musculoskeletal, biomechanical and neuromuscular systems. If you want to get to know me better, I enjoy long walks on the beach and that Physiology Reports study.

A 2017 study in the Journal of Strength and Conditioning Research similarly took 16 trained trail runners and had them complete two weeks of 4 to 7 x 30 seconds hard with 4 minutes of recovery 3 times per week. They improved in their 3K time trial times by about 6 percent, with similar physiological underpinnings. Physiology Reports, baby, I promise you're the only journal for me. I just like the Journal of Strength and Conditioning Research's photo composition on Instagram. It's purely artistic respect!

Running economy improvements seen with the introduction of faster strides would apply to the remainder of training-more sustainable speed in workouts and likely more efficient easy running too.

Do the initial adaptation processes eventually level off or even decrease? That's tough to measure (for more, see this 2017 study in the Journal of Applied Physiology and this 2017 study in the Scandanavian Journal of Medicine & Science in Sports), but I doubt it. Running economy improvements seen with the introduction of faster strides would apply to the remainder of training-more sustainable speed in workouts and likely more efficient easy running too. Add well-rounded training on top of the speed development (plus periodization of different stimuli), and there should be positive feedback cycles that improve the aerobic system.

Training Systems

From the 1950s on, strides have played an important role in training approaches. Starting in the 1950s, Coach Mihaly Igloi had a system predicated on stride-like intervals (see this wonderful article from Coach Steve Magness). In the 1960s and 1970s, Arthur Lydiard pioneered modern training approaches with strides and hills building off base periods. And now, coaches from Renato Canova to Jack Daniels include short, fast bouts of running in various ways. In trail and ultra running, strides have been key component parts of the training of athletes like Clare Gallagher, Hayden Hawks, Jason Schlarb, Katie Asmuth and many others.

All of that was a glorified preamble for the big questions of the day: how do you actually do strides, and how do they fit into a well-rounded training plan? Now, we are venturing into an area where there is even more debate, so I will summarize what Megan and I recommend, but find what works for you.

How To Run Strides

For athletes we coach, strides are 15- to 30-second accelerations to the fastest pace they can go without straining or sprinting, usually with 1 to 2 minutes easy running recovery between. Our usual guideline is to do 4 to 8 of them, with 4 being the sweet spot balancing stimulus and stress. They can be on roads or non-technical trails, flat ground or slight ups and downs.

It's key to avoid full, arms-pumping sprinting due to the risk of injuries and reinforcing biomechanical patterns that are not conducive to long-distance running. The cap at 30 seconds is to prevent too much stress, which could undermine the aerobic system (see this article on base training for more). We like athletes to apply four cues:

Ease into the effort, with the first 5 seconds gradually building pace, emphasizing longer strides before rapid turnover;

Run tall through the hips, with a slight forward lean;

Use long-distance form, with normal arm carriage and a relaxed upper body;

Instead of increasing cadence as high as you can go, emphasize knee drive and output-per-stride at a smooth effort.

Put it all together, and it usually equates to between the speed an athlete could race 800 meters to a mile (for beginner to intermediate athletes) or a mile to 3K or even 5K (for intermediate to very advanced athletes). More slow-twitch athletes can usually go toward the faster end, and faster twitch athletes should stay on the slower end. If you do them on non-technical trails, the paces will be slower, and that's OK too.

When To Run Strides

Now, it's important to consider how flat strides fit in with hill strides. Hill strides primarily emphasize the musculoskeletal system, since the uphill grade usually involves lower cadence and increased power-per-stride. Meanwhile, flat strides emphasize the neuromuscular and biomechanical systems, with higher cadence and more strain on form. A strong cyclist who doesn't run could probably do a good hill stride due to their power, but would likely suffer on a flat stride due to their lack of neuromuscular and biomechanical adaptations.

Hill strides primarily emphasize the musculoskeletal system, since the uphill grade usually involves lower cadence and increased power-per-stride. Meanwhile, flat strides emphasize the neuromuscular and biomechanical systems, with higher cadence and more strain on form.

After a base period of easy running, we like athletes to start with hill strides, improving raw musculoskeletal output first with lower overall risk. If athletes are over 50, prone to injuries, or find themselves going too fast on flat strides, they may never do flat strides at all.

Other athletes usually progress into flat strides after they are fully adapted to the hill stride stimulus. The choice of flats or hills will alternate depending on goals (more hills for ultramarathoners, more flats for road racers) and genetic predispositions (more hills for faster-twitch athletes, more flats for slower-twitch athletes).

Rest between strides starts as near-complete recovery (1-2 minutes), so that fatigue does not impact form or output significantly. Later, the rest may shorten to as little as 30 seconds to get an enhanced aerobic stimulus, particularly closer to races or for faster-twitch athletes.

Most of our athletes do strides one to three times per week. You can generally add them during any easy run, with the caveat that there could be some aerobic drawbacks to doing too many strides too often. Before workouts, they make a great neuromuscular primer. After harder efforts, they can serve as a combo workout stimulus.

A typical weekly breakdown for an intermediate/advanced athlete in the middle of a training cycle may look like this:

Monday: Rest Day

Tuesday: 8-10 miles easy with 5 x 20 seconds fast/1 min easy flat strides

Wednesday: 3 miles easy, workout (like 6-8 x 3 minutes at 10k effort with 2 minutes easy recovery), 4 x 20-30 second hill strides, 3 miles easy

Thursday: 8-10 miles easy

Friday: 4-6 mile easy or x-train

Saturday: 14 miles easy/moderate (20 minutes moderately hard around 1-hour effort)

Sunday: 10 miles easy with 4 x 20-30 seconds fast/2 min easy flat strides

Before you get overwhelmed, let's end the article with a step back to the first principles of strides. The basic idea is that going faster than you'll ever race (but not as fast as you absolutely can) will make you faster overall at all effort levels. That improved running economy is balanced against injury risk and a slight chance of aerobic regression if done too intensely or at the exclusion of other types of training. Start with hill strides, and only do flat strides if you feel confident in your health and discipline to avoid all-out sprinting. You can add them to almost any run, but don't add them to every run.

And most importantly, don't stress about the exact details. Just make sure that you remember one thing: you are an ATHLETE. And exploring your unlimited athletic potential may be a bit more fast (and fun) with strides.

posted Sunday January 24th
by Trail Runner Magazine