What Is Running Economy? Definition, Physiology & Training Guide

Running economy is a term most runners have heard — but for many, the understanding stops at “something to do with running efficiency.”

In fact, running economy is one of the three primary physiological determinants of distance running performance, alongside VO2 max and lactate threshold ※1.

Two runners with identical VO2 max values can differ by 10 to 20 minutes in a full marathon — purely because of differences in running economy.

This article explains running economy quantitatively: from its definition and measurement methods to the physiological mechanisms behind it and the training strategies that improve it, drawing on peer-reviewed research.

What Is Running Economy? Definition and Measurement

The Oxygen Cost Definition (mL/kg/km)

Running economy (RE) is the amount of oxygen consumed per kilogram of body weight per kilometer traveled at a given submaximal speed. It is expressed in units of mL/kg/km (milliliters per kilogram per kilometer).

A lower value means less oxygen is needed to cover the same distance — in other words, a more fuel-efficient runner. Well-trained distance runners typically fall in the range of 180–220 mL/kg/km, with elite runners tending to be considerably lower.

Measurement is performed on a laboratory treadmill. Expired gas analysis is conducted during steady state — when the body has adapted to the target speed and oxygen consumption has stabilized, typically after 8 minutes of running — and running economy is calculated from the oxygen consumption data ※3.

Incremental protocols, where speed is raised in stages, have also been confirmed to produce reliable running economy measurements ※4, making repeated testing during normal training periods feasible.

Notably, running economy values remain relatively stable across speeds. Below approximately 90% of VO2 max, the oxygen cost per kilometer changes very little even as pace changes ※4.

This means that comparisons at specified speeds — such as “running economy at 5:00/km” versus “running economy at 4:30/km” — are valid, and values measured at different speeds can be meaningfully compared.

How Running Economy Differs from VO2 Max

VO2 max represents the ceiling — the maximum oxygen uptake per minute. Running economy, by contrast, represents how efficiently that oxygen consumption is converted into speed. They are independent measures.

VO2 max (in mL/kg/min) reflects the oxygen delivery capacity of the heart and lungs. Running economy reflects how efficiently that consumed oxygen is converted into forward propulsion.

The two are independent capacities: a high VO2 max does not guarantee fast race times if running economy is poor ※1.

Importantly, even among elite runners, running economy shows more than a 21% spread between individuals ※5. In competitive groups where VO2 max values cluster closely together, this variation in running economy becomes the primary driver of performance differences ※7.

Measuring Running Economy with Wearables

Certain Garmin devices (such as the Fenix series) include a running economy estimation feature. These values are derived indirectly from accelerometer data, heart rate sensors, and gait metrics — they differ from direct laboratory measurement.

The most practical use for wearable estimates is tracking personal trends over time, not comparing absolute values with other runners. Running the same route under consistent conditions and monitoring changes is a more appropriate application.

How Running Economy Affects Marathon Performance

The Three Factors That Determine Race Time

Research consistently identifies three physiological factors as the primary determinants of long-distance running performance: VO2 max, lactate threshold (LT), and running economy (RE) ※1.

VO2 max sets the ceiling — the maximum oxygen available per minute. Lactate threshold determines what fraction of that ceiling can be sustained throughout a race.

Running economy determines how efficiently that oxygen consumption translates into actual speed. Together, these three factors combine to produce race times ※2. For a side-by-side comparison of how all three interact, see VO2 Max, Lactate Threshold & Running Economy Explained.

Even in middle-distance events like the 800m and 1500m, combining VO2 max and running economy statistically explains nearly 96% of the variation in performance ※6. Running economy is not limited to long-distance events.

Why Two Runners with the Same VO2 Max Can Differ by 20 Minutes

Consider two runners with identical VO2 max values (55 mL/kg/min) and identical lactate thresholds (80% of VO2 max). If only their running economy differs, what happens to their marathon times?

Running the numbers: a runner with RE 200 sustains approximately 13.2 km/h (marathon time around 3:11), while a runner with RE 220 sustains approximately 12.0 km/h (marathon time around 3:31).

With the same VO2 max and lactate threshold, the difference in running economy alone produces a 20-minute gap in marathon time.

This illustrates why improving running economy can sometimes be more practical than improving VO2 max — especially at higher competitive levels, where VO2 max values tend to converge and running economy becomes the main performance differentiator ※7.

How Much Does a 5% Improvement in Running Economy Change Your Time?

A key insight from Joyner’s (1991) physiological model is that percentage improvements in running economy translate almost directly into equivalent percentage reductions in marathon time ※2.

For a runner finishing a marathon in 3:30 (210 minutes), a 5% improvement in running economy reduces the time by approximately 5%.

5% of 210 minutes is about 10.5 minutes — equivalent to a 10–11 minute improvement, bringing the time into the 3:19–3:20 range.

For a runner at 3:00 exactly, the same 5% improvement yields roughly a 9-minute reduction (finishing around 2:51). Over several years of consistent training, gains of 10–20% in running economy are realistic, making the cumulative impact substantial ※2.

On the question of whether LSD running hurts running economy: the evidence points in the opposite direction. Long-term accumulation of aerobic training volume — including easy long runs — is one of the primary drivers of running economy improvement ※12. Sustained aerobic training, including jogging and longer runs, improves running economy progressively over time.

What Determines Running Economy?

Why do individuals differ so widely in running economy? Research points to three main categories: biomechanics, neuromuscular and elastic energy systems, and metabolic and muscle fiber composition.

Biomechanical Factors

A study by Folland et al. (2017) simultaneously measured full-body 3D motion analysis and running economy in 97 runners across a wide range of performance levels ※8.

The key finding was that no single gait variable — such as minimizing vertical oscillation or tilting the pelvis forward — independently predicted running economy. Instead, a composite technique score combining vertical oscillation, braking, posture, stride length, and lower limb angles was an independent predictor of running economy.

In particular, shorter ground contact time shows a strong correlation with running economy. Research on Kenyan female distance runners found a high correlation between ground contact time at threshold intensity and running economy ※9.

That said, consciously trying to shorten ground contact time is less effective than allowing it to decrease naturally through consistent training.

On pelvic tilt: a slight forward lean of the trunk supports propulsion, but excessive forward lean may actually worsen running economy ※8. The simple rule of “more anterior pelvic tilt is always better” is not accurate.

Elastic Energy and Tendon Stiffness (The Key Mechanism)

Among all the factors that differentiate running economy, tendon elastic energy reuse has the strongest body of evidence behind it.

At foot strike, the Achilles tendon and other lower-limb tendons deform and store mechanical energy. At toe-off, this stored energy is released as propulsive force.

This elastic energy recycling requires almost no muscular energy (ATP), which means higher tendon stiffness leads to more economical running.

A 14-week calf strengthening intervention (Albracht 2013) produced approximately 16% increase in tendon stiffness, with a corresponding approximately 4% reduction in oxygen consumption during running.

A strong correlation was confirmed between the increase in tendon stiffness and the improvement in running economy ※10.

The morphological characteristics of the Achilles tendon — such as moment arm length — are also related to running economy ※5. While these are partly genetic and cannot be changed, tendon stiffness can be improved through training, offering a meaningful avenue for economy gains.

Metabolic and Muscle Fiber Composition

On the metabolic side, higher mitochondrial density and oxidative enzyme activity in skeletal muscle lower the metabolic cost of running at any given pace ※1.

Long-term aerobic training improves running economy through this mitochondrial adaptation.

In terms of muscle fiber composition, a higher proportion of slow-twitch fibers (Type I) supports more efficient aerobic energy metabolism, which tends to favor long-distance running economy.

However, muscle fiber composition is largely genetic and cannot be dramatically altered through training.

A common misconception: “poor running economy means more fat burning.” A higher oxygen cost per kilometer means more total energy is expended to cover the same distance. But whether fat or carbohydrate is the primary fuel depends on exercise intensity (%VO2 max), not running economy. The two are not directly linked.

How to Improve Running Economy

Mileage Accumulation (The Foundation)

The most fundamental way to improve running economy is through long-term accumulation of aerobic training. Training history and cumulative training volume — including long-distance runs — have been confirmed as the most important factors in running economy improvement ※12.

The mechanisms are multiple and overlapping: consistent mileage optimizes the elastic properties of tendons, increases mitochondrial density for more efficient energy metabolism, and improves neuromuscular coordination to reduce unnecessary muscle activation.

These adaptations occur over months and years, which is why consistent mileage accumulation carries genuine long-term value.

Long slow distance (LSD) runs, performed once or twice a week, contribute to running economy improvement over time rather than reducing it.

The belief that “LSD worsens running economy” likely stems from short-term fatigue measurements being misinterpreted as a lasting effect.

Heavy Resistance Training

A meta-analysis (Balsalobre 2016) confirmed that even highly trained runners (VO2 max ≥ 60 mL/kg/min) show meaningful running economy improvements from adding resistance training alone ※15.

A separate meta-analysis (Eihara 2022) found that heavy resistance training outperforms plyometric training for improving running economy ※13.

The effect is largest when loads of 90% or more of one-repetition maximum (1RM) are used.

The primary mechanism is increased tendon stiffness ※10. Heavy resistance training strengthens the Achilles tendon and lower-limb tendons, improving elastic energy storage and release efficiency. Neuromuscular coordination also improves, reducing total muscle activation required at a given pace.

Recommended exercises include squats, leg presses, and calf raises. Effects begin to appear after 8 or more weeks of training twice per week, with greater improvements seen over longer durations.

Plyometric Training

A 6-week plyometric training intervention using depth jumps (Spurrs 2003) produced an approximately 2.7% improvement in 3km time and improved running economy — without any change in VO2 max or lactate threshold ※11.

The study found a strong correlation between increases in tendon stiffness and improvements in running economy, suggesting that enhanced elastic energy utilization is the primary mechanism.

The fact that race times improved without changes in VO2 max or lactate threshold is significant — it confirms that running economy alone drove the performance gain, supporting a direct mechanism through plyometric training.

In meta-analyses, however, plyometric training tends to show a somewhat smaller effect on running economy compared to heavy resistance training ※13. Combining both approaches produces the greatest benefit.

High-Speed Running and Combined Programs

A study by Rodriguez-Barbero et al. (2023) implemented an 8-week combined program incorporating low-intensity continuous running, HIIT (high-intensity interval training), and supplementary resistance training ※17.

The result was an approximately 6% reduction in oxygen cost and approximately 5% reduction in energy cost.

Similar improvements were seen in both experienced and recreational runners, demonstrating the broad applicability of combined programs.

For long-distance races, “running economy durability” is also important. Some runners who are economical early in a race see their running economy deteriorate significantly after 90 minutes.

A resistance training intervention (Zanini 2025) showed that the deterioration of running economy after 90 minutes of running was reduced, improving fatigue resistance ※16. This finding is particularly relevant for marathon runners.

Running Shoes and Running Economy

Carbon Plate Running Shoes (AFT) and Their Effects

Carbon plate running shoes — also known as advanced footwear technology (AFT) — improve running economy independently of training adaptations or physical fitness.

A study comparing AFT spikes, non-AFT spikes, and conventional road shoes at the same speed (16 km/h) found that AFT spikes produced the greatest improvement in running economy (Warne 2024) ※18.

The mechanism involves the combination of a thick foam midsole and a carbon fiber plate. At landing, the foam deforms to store elastic energy; at toe-off, that energy is released to assist propulsion.

The running economy improvement from AFT is typically in the range of 2–4%, varying by individual. As shown in the previous section, a 2–4% improvement translates to approximately 3–8 minutes off a full marathon. Using AFT in races is a rational choice.

Why Switching to Minimalist Shoes Feels Harder

Runners who have trained primarily in carbon plate shoes often find that switching to minimalist shoes or conventional trainers makes the same pace feel harder, with greater fatigue in the calves and plantar fascia.

This is because without the shoe’s elastic assistance, the lower limb muscles and tendons must compensate directly. Running in minimalist shoes places a greater neuromuscular demand on the lower limbs — which makes periodic use in training an effective strategy for improving tendon stiffness.

That said, an abrupt transition concentrates stress on the calves and plantar fascia, so a gradual shift is recommended.

Summary: Running Economy Improvement Checklist

Running economy is one of the three primary determinants of running performance, alongside VO2 max and lactate threshold. With the same VO2 max, differences in running economy can produce a 10–20 minute gap in marathon time.

A 5% improvement in running economy corresponds to roughly a 9–11 minute improvement in marathon time.

Here is a practical checklist for improving running economy.

References

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※2 Joyner MJ. Modeling: optimal marathon performance on the basis of physiological factors. J Appl Physiol. 1991;70(2):683-7.

※3 Brady AJ et al. Test-Retest Reliability of Running Economy and Metabolic and Cardiorespiratory Parameters During a Multistage Incremental Treadmill Test in Male Middle- and Long-Distance Runners. Int J Sports Physiol Perform. 2024.

※4 Helgerud J, Støren O, Hoff J. Are there differences in running economy at different velocities for well-trained distance runners? Eur J Appl Physiol. 2010;109(3):473-9.

※5 Hansen CE et al. Factors correlated with running economy among elite middle- and long-distance runners. Eur J Sport Sci. 2022;22(6):837-845.

※6 Ingham SA et al. Determinants of 800-m and 1500-m running performance using allometric models. Med Sci Sports Exerc. 2008;40(2):345-50.

※7 Denadai BS, Greco CC. Could middle- and long-distance running performance of well-trained athletes be best predicted by the same aerobic parameters? Int J Environ Res Public Health. 2022;19(13):7985.

※8 Folland JP et al. Running Technique is an Important Component of Running Economy and Performance. Med Sci Sports Exerc. 2017;49(7):1412-1423.

※9 Mooses M et al. Ground contact time and running economy among Kenyan female middle-long distance runners. Int J Sports Physiol Perform. 2021.

※10 Albracht K, Arampatzis A. Exercise-induced changes in triceps surae tendon stiffness and muscle strength affect running economy in humans. J Exp Biol. 2013;216(Pt 2):244-51.

※11 Spurrs RW, Murphy AJ, Watsford ML. The effect of plyometric training on distance running performance. Eur J Appl Physiol. 2003;89(1):1-7.

※12 Barnes KR, Kilding AE. Strategies to improve running economy. Sports Med. 2015;45(1):37-56.

※13 Eihara Y et al. Heavy Resistance Training Versus Plyometric Training for Improving Running Economy and Running Time Trial Performance: A Systematic Review and Meta-analysis. Sports Med Open. 2022;8(1):152.

※14 Denadai BS et al. Explosive and Heavy Resistance Training Improve Running Economy in Well-Trained Athletes. Front Physiol. 2017;8:891.

※15 Balsalobre-Fernández C, Santos-Concejero J, Grivas GV. Effects of Strength Training on Running Economy in Highly Trained Runners: A Systematic Review With Meta-Analysis of Controlled Trials. J Strength Cond Res. 2016;30(6):1770-84.

※16 Zanini M et al. Effects of concurrent strength and endurance training on running economy durability. RCT. 2025.

※17 Rodriguez-Barbero S et al. Effects of a Regular Endurance Training Program on Running Economy and Biomechanics in Runners. Applied Sciences. 2023;13(19):10982.

※18 Warne JP et al. AFT track spikes versus non-AFT spikes and road shoes: running economy at 16 km/h. Int J Sports Physiol Perform. 2024.