Running Economy Explained: What Biomechanics Teaches Us

I have two athletes with nearly identical VO2max. One runs a 10K in 34 minutes. The other, in 37. The difference isn't in the engine — it's in how much oxygen each one needs to hold the same pace. That's running economy, and it's one of the least understood variables among recreational runners and, honestly, among plenty of coaches too.

What Running Economy Is (and Why VO2max Isn't Enough)

Running economy (RE) is defined as the oxygen cost of running at a given submaximal speed. Put simply: if two runners have the same VO2max, whoever consumes less oxygen at a 7:15 min/mile pace is more "economical" and, all else equal, faster on race day.

For years, VO2max was treated as the king metric of distance performance. But research from Saunders and Pyne made clear that RE explains performance variability that VO2max doesn't [PMID:15233599]. Among runners of similar caliber, economy is often the factor that separates the one who stands on the podium from the one who finishes mid-pack.

What's interesting is that RE isn't a single mechanism — it's a blend of physiology, biomechanics, environment, and even footwear. But in this article I want to focus on the biomechanical piece, because it's the one that gives runners and coaches the most control.

The Biomechanical Factors That Move the Needle

Saunders and Pyne identified several biomechanical elements associated with better economy [PMID:15233599]:

Stride length and cadence. There's no universal "ideal stride," but there is an optimal range for each runner. Overly long strides generate braking forces at every footstrike — the foot lands ahead of the center of mass and acts as a microscopic brake with each step. Thousands of repetitions of that brake over a race cost oxygen.

Musculotendinous stiffness. A stiffer tendon system stores and returns elastic energy more efficiently, like a spring. Runners with stiffer Achilles tendons tend to be more economical because they take better advantage of the stretch-shortening cycle with every stride.

Vertical displacement of the center of mass. Every extra centimeter the body rises and falls with each stride is energy spent on an axis that adds nothing to horizontal speed. Economical runners tend to minimize that vertical oscillation without eliminating it entirely — some bounce is normal and even necessary.

Symmetry and neuromuscular coordination. Small asymmetries — a hip that rotates more on one side, an arm that crosses the midline — aren't just visual curiosities. They represent extra muscular work to compensate, and that work also burns oxygen.

None of these factors act alone. Economy is a system, not a checklist.

The Role of Strength: The Strongest Evidence of Recent Years

If you ask me which intervention has the best evidence-to-effort ratio for improving economy, the answer is strength training. And it's no longer a coach's hunch — it's a consistent body of evidence.

A systematic review with meta-analysis published in 2024 examined the effect of different strength programs on running economy at various speeds in middle- and long-distance runners [PMID:38165636]. The overall conclusion: strength training consistently improves running economy, and the effects hold across different running speeds, not just at race pace.

This makes biomechanical sense: maximal strength and power improve the musculotendinous system's ability to generate force quickly with each ground contact, which translates into shorter ground contact time and better use of elastic energy — exactly the mechanisms Saunders and Pyne described as determinants of RE [PMID:15233599].

A more recent 2025 study went a step further: it investigated not just "fresh" running economy but its durability — that is, how much economy deteriorates after accumulated effort, which is what actually happens in a long race. Zanini and Folland found that strength training improved both running economy in a fatigued state and high-intensity performance after accumulated fatigue, in well-trained runners [PMID:40016936].

I think this is the most relevant finding for marathon and half-marathon runners. The economy you measure in a fresh lab test at mile 1 isn't the same economy you have at mile 20, exhausted. If strength protects that economy when the body is already fatigued, the impact on long races is direct and measurable.

Why This Matters Especially in the Marathon

Jones and Kirby studied the physiological demands of running at a 2-hour marathon pace [PMID:33151776]. One key finding: at intensities sustained for more than two hours, small improvements in economy translate into energy savings that accumulate exponentially over the course of the race. Saving 1-2% of oxygen cost isn't the same over a 15-minute effort as it is over a 130-minute one.

This reinforces something I try to explain to my marathon athletes: running economy isn't an elite luxury — it's a central variable for any runner competing in distances where accumulated fatigue erodes technique. If your stride falls apart at mile 20 because you don't have the strength to sustain it, that's not a "mental toughness" problem — it's a mechanical problem with a mechanical solution.

Practical Application: What to Do With This

With my runners, running economy gets worked on two parallel fronts, not just one:

1. Structured strength training, year-round. I'm not talking about "doing some squats now and then." I mean 2 strength sessions per week with real load progression, including maximal strength work (3-6 rep ranges with heavy loads) and plyometric or power work. The evidence shows benefits in economy across different speeds [PMID:38165636] and under fatigue conditions [PMID:40016936], so I don't reserve strength work just for the off-season — I maintain it through the whole training cycle, adjusting volume based on running load.

2. Specific technical work, not generic drills. Technique drills without a clear purpose don't change much. What does help is identifying each runner's specific pattern — does the hip collapse? Is there too much vertical movement? Is there braking on every stride from overstriding? — and working that specific pattern with targeted exercises, not a one-size-fits-all track-drill routine copied from the internet.

3. Volume progression at specific paces. Economy is also trained by running. Marathon-pace, tempo, and threshold sessions teach the neuromuscular system to organize itself efficiently at those specific speeds. It's not enough to be economical jogging easy — you need to be economical at the speed you're going to race.

4. Don't ignore accumulated fatigue in training. If the goal is a marathon, I include quality work in the second half of long runs — not because I want to wreck the athlete every week, but because I need to expose them to maintaining good mechanics under fatigue, which is exactly the condition Zanini and Folland described as trainable [PMID:40016936].

An Important Caveat: Economy Isn't Everything

It's worth saying this clearly: improving running economy doesn't replace aerobic work or threshold work. These are complementary systems. An extremely economical runner with a low VO2max or a poor lactate threshold will still have a low performance ceiling. Economy multiplies what you already have physiologically — it doesn't replace it.

And while the angle of this article is biomechanical, I don't ignore that metabolic factors also play into a runner's overall energy efficiency equation. Recent research in animal models, for example, explores how different fasting protocols combined with exercise regulate glucose metabolism through pathways like AMPK/SIRT1/BDNF [PMID:40765038]. It's an emerging area still far from translating into clear practical recommendations for human runners, but it confirms that the efficiency with which the body uses energy goes beyond pure stride mechanics.

Conclusion

Running economy is trainable, measurable, and in many cases more decisive for performance than chasing a higher VO2max. Biomechanics — stride, tendon stiffness, vertical oscillation, symmetry — explains a good part of why some runners burn less oxygen than others at the same speed. And the intervention with the strongest recent scientific backing for improving it, even under fatigue, is well-structured strength training.

If you've been stuck at the same pace for months despite consistent volume, it's worth asking: is this an engine problem, or a question of how much fuel your engine burns to move the same body at the same speed? For a lot of runners, the answer lies more in the gym than they'd think.

References

• Saunders PU, Pyne DB, et al. Factors affecting running economy in trained distance runners. Sports Med. 2004. [PMID:15233599]
• Llanos-Lagos C, Ramirez-Campillo R, et al. Effect of Strength Training Programs in Middle- and Long-Distance Runners' Economy at Different Running Speeds: A Systematic Review with Meta-analysis. Sports Med. 2024. [PMID:38165636]
• Zanini M, Folland JP, et al. Strength Training Improves Running Economy Durability and Fatigued High-Intensity Performance in Well-Trained Male Runners: A Randomized Control Trial. Med Sci Sports Exerc. 2025. [PMID:40016936]
• Jones AM, Kirby BS, et al. Physiological demands of running at 2-hour marathon race pace. J Appl Physiol (1985). 2021. [PMID:33151776]
• Wang X, Shi J, et al. Different Fasting Methods Combined With Running Exercise Regulate Glucose Metabolism via AMPK/SIRT1/BDNF Pathway in Mice. Compr Physiol. 2025. [PMID:40765038]