VO2max Was Associated With Physiological Resilience During Running

Thomas Solomon, PhD

Endurance capacity changes as fatigue builds. This study examined which traits were associated with preserving running speed and economy during prolonged running.

Reference: Malinen et al. Determinants of Physiological Resilience Among Recreational-To-Competitive Endurance Runners. Scandinavian Journal of Medicine & Science in Sports (2026) DOI: 10.1111/sms.70349.

Medical informationThis article is for general educational purposes only and is not medical advice. Supplements and exercise/recovery interventions can cause side effectsAn additional effect of a treatment that is not the main intended effect. It may be harmful, harmless, or helpful, while an adverse effect is specifically harmful. and may interact with medicines, nutrients, or medical conditions. Speak with a doctor or suitably qualified healthcare professional before making changes if you have a medical condition, take medications, are pregnant or breastfeeding, or are unsure what is safe for you.

Study snapshot

A quick, practical summary for runners and coaches.

Quick answer

This cross-sectional laboratory studyA cross-sectional study is a type of observational study where the exposure and outcome are measured at a single point in time, giving a snapshot of a population—what’s happening right now. Cross-sectional studies are used in health surveys, prevalence studies, or for hypothesis generation, and can show prevalence (how common something is) and associations (but not cause and effect). E.g., What percentage of runners currently report using recovery supplements, and is use linked to age or training volume? examined physiological resilienceDurability is a measure of how “durable” your physiological performance metrics are during prolonged fatigue-inducing exercise. I.e., can you still produce your maximal power at the end of a hard 2 hour run? during about 2.5 hours of running in 33 trained runners. Greater aerobic fitness and leg strength were associated with less deterioration in some outcomes, but the small observational studyAn observational study is where researchers observe what naturally occurs without intervening — no treatment is assigned. I.e., the researchers watch and learn, but don’t interfere. Observational studies are used in epidemiology and can have different study designs, including cross-sectional, case-control, and cohort study designs. cannot show that improving these traits will improve resilience.

Key takeaways

  • Greater aerobic fitness was associated with better preservation of some running-speed measures.
  • Greater leg strength was associated with a smaller deterioration in running economyThe rate of energy expenditure (measured in kiloJoules [KJ], kilocalories [kcal] or oxygen consumption [VO2]) per kilogram body mass (kg) per unit of distance, i.e. per 1 kilometre travelled. A runner with a lower energy cost per kilometre has a higher economy than a runner with a higher energy cost..
  • The findings offer useful clues, but they do not identify a proven durability-training method.

How confident should we be?

Evidence confidence: Low

The researchers used detailed, runner-specific laboratory testing. The small sampleN is how many participants or observations are analyzed. A bigger N usually means more precise estimates and more power (ability to detect a true effect). A smaller N results in a study that is less likely to detect a true effect (false negative/type II error) and is more likely to report false positives (type I error). Of course, a badly designed study is still bad even if it has a big N., cross-sectional design, and numerous exploratory correlations mean that the findings need confirmation.

Bottom line

Aerobic fitness and leg strength may form part of a runner’s ability to resist fatigue-related decline. Keep developing both, but do not rebuild your training plan around this study alone.

Read the deep dive below to get a practical interpretation, the wider evidence, some actionable decisions, my thoughts, my rating of perceived scientific enjoyment, and the full study details (research question, study design, participants, methods, results, and the strengths & limitations).

Running science research reviews for endurance runners

The deep dive

The details behind the headline result, including the practical meaning, full findings, limitations, and my interpretation.

Practical meaning

What does this research mean for runners and coaches?

Physiological resilience, sometimes called durability, describes how well a runner preserves important physiological qualities as fatigue builds.

A runner may have an impressive maximal oxygen uptakeVO2max is the maximal rate of oxygen consumption your body can achieve during exercise. It is a measure of cardiorespiratory fitness and indicates the size of your engine, i.e., your maximal aerobic power, which contributes to endurance performance., threshold pace, or running economy while fresh. That does not necessarily mean those qualities remain equally impressive after 2 hours of running. Fitness has a late-race version, and it may not look quite as polished.

The researchers found that different parts of resilience were associated with different physiological traits. Aerobic fitness was associated with the preservation of some running-speed measures. Leg strength was associated with the preservation of running economy. No single baselineThe measurements taken before the intervention begins, used as the “before” or “pre-study” point for comparison with “after” or “post-study” measurements. measurement explained every outcome.

That matters because resilience probably is not 1 standalone ability. It appears to reflect several overlapping systems, including oxygen transport, muscle metabolism, strength, movement efficiency, and perhaps muscle-fibre characteristics.

For runners

The study suggests that fresh fitness measurements do not tell the whole story. A runner with a strong maximal oxygen uptake or fast threshold pace may still experience a substantial decline during prolonged running.

This is relevant to marathon runners, who need to preserve pace and efficiency after several hours of work. The laboratory test covered about 22 km in the recreational runners and 28 km in the competitive runners, so the duration and distance had some marathon relevance.

The resemblance was far from perfect, though. The runners worked below typical marathon intensity for many competitive athletes, consumed no external energy (calories from carbs), ran on a treadmill, and the protocol was not a race simulation.

The results are less directly applicable to trail runners. The treadmill did not reproduce uneven surfaces, climbing, descending, technical footing, or the additional muscle damage often caused by downhill running.

The findings are also only partly relevant to ultra runners. Some participants had an ultrarunning background, but a 2.5-hour treadmill test does not recreate the duration, terrain, feeding demands, or pacing of an ultra.

For coaches

The findings support treating resilience as an extra layer of athlete profiling rather than a replacement for maximal oxygen uptake, threshold testing, or running economy.

One practical interpretation is to compare how an athlete performs while fresh with how they perform late in a standardised long session. Useful field observations could include pace at a set heart rate, heart rate at a set pace, perceived effort, movement quality, and the ability to complete faster running late in the session.

The study did not validate those field measures, so this is a coaching interpretation rather than a direct finding.

Standardisation matters. Weather, terrain, fuelling, footwear, prior training, and sleep can all change late-run performance. Without reasonable control, you may be measuring the effects of a Wednesday rather than durability.

Evidence in context

What does the wider evidence say?

Earlier research suggests that physiological resilience — the ability to limit deterioration in measures such as running economy, thresholds, and maximal aerobic performance during prolonged exercise — may help explain endurance performance beyond fresh laboratory values (Jones et al. 2024). However, studies use varied exercise protocols and outcome measures, making direct comparisons difficult (Peeters et al. 2025). Reviews propose possible roles for aerobic fitness, muscle characteristics, fuel availability, and strength, but the underlying determinants remain uncertain and evidence on how resilience can be trained is still limited (Jones et al. 2025).

How this study fits: This study adds running-specific evidence rather than overturning earlier work. Different resilience measures were associated with different characteristics: aerobic fitness was linked to smaller declines in threshold and maximal running speed, while greater leg strength was linked to better preservation of running economy. These cross-sectional associations cannot establish cause and effect, but they refine the idea that resilience is not one ability governed by one physiological factor.

Practical decision

Should runners change anything?

Maybe. The study supports familiar training principles rather than introducing a new workout.

Consider this if

  • Your pace or movement quality repeatedly deteriorates sharply late in long runs.
  • Your fresh laboratory results look strong, but your longer races regularly fade.
  • Your training includes plenty of running but little progressive strength work.
  • You only assess fitness while rested.

Do not overreact if

  • 1 long run goes badly after poor sleep, heavy training, heat, or inadequate fuelling.
  • Your heart rate rises late in a run, because dehydrationThe physiological fact that water is leaving the body (in your breath, sweat, tears, pee, poop, breast milk, blood, and puke). and temperature can contribute.
  • You already follow a balanced programme that develops aerobic fitness, strength, and race-specific endurance.
  • Your running economy worsens slightly during a demanding long session.

A sensible next step

Continue following an appropriate aerobic and strength-training programme. Add occasional standardised long sessions that help you observe how well pace, effort, and movement quality hold up when tired.

This study did not establish the best aerobic workout, the ideal strength-training dose, or a specific protocol for improving physiological resilience.

TIP: Never make any major changes to your training or lifestyle habits based on the findings of one study, especially if the study is small or provides low-quality evidenceA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and future studies could easily change overall conclusions. The best way to improve the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Check whether other trials confirm the findings. If there is a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. on the topic, look at the effect sizeA standardised measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show the size of the effect and how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients., the variability between studies, and the quality of evidenceCertainty of evidence tells us how confident we are that the published results accurately reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, precision, and publication bias. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. Whereas, low certainty means more doubt and less confidence, and that future studies could easily change current conclusions..

Expert interpretation

My thoughts

Running science from Thomas Solomon at Veohtu

This is a useful study because it treats endurance fitness as something that changes during exercise rather than a permanent number printed on a laboratory report.

The clearest message is that physiological resilience was not 1 simple trait. Fitter runners preserved some outcomes better. Stronger runners preserved another. No baseline measure explained everything.

That makes physiological sense. Maximal oxygen uptake, threshold speed, and running economy depend on overlapping but distinct systems. It would be surprising if 1 shiny metric ruled them all.

The association between leg strength and running-economy resilience is particularly interesting. It also fits with previous intervention research suggesting that strength training can help runners preserve economy during prolonged running (Zanini et al. 2025). This study did not test strength training, though, so it cannot show that becoming stronger caused better resilience.

The group comparison also needs care. The competitive runners covered about 6 km farther than the recreational runners during the fixed-duration test. They also lost more body mass. Because the researchers calculated running economy relative to body mass, this affected the apparent difference between the groups.

A later analysis using absolute energy expenditure found no clear group difference. The initial result therefore needs to be interpreted with caution.

The study should not cause a major change in practice. It supports developing aerobic fitness, strength, and the ability to perform well when tired. The next step is to test whether targeted training actually improves specific resilience outcomes and whether those improvements translate into better race performance.

Fresh fitness is useful. The more interesting question is how much remains when the finish line is still several uncomfortable kilometres away.

My Rating of Perceived scientific Enjoyment

owlRPsE: 5/10

I experienced low scientific enjoyment because although the study used detailed, relevant testing and reported meaningful outcomes, the small cross-sectional sample and numerous exploratory correlations limited confidence. It offers useful clues for runners and coaches, rather than firm training instructions.

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Read on for further details about the methods, results, strengths, limitations, and conflicts of interest.

Research question

What did the researchers ask?

The authors aimed to find out whether common determinants of endurance performance were associated with physiological resilience in trained runners.

They examined whether maximal oxygen uptake, threshold speeds, running economy, fat oxidationFat oxidation is the process where your body breaks down fat and uses it for energy, again usually with oxygen. It’s a key way your body fuels longer, steadier efforts and daily living., anaerobic characteristics, and leg strength were associated with changes during prolonged running.

The authors also compared physiological resilience between recreational and competitive runners.

Study design

What type of study was this?

This was a cross-sectional observational study involving repeated laboratory tests.

The researchers measured the runners’ existing physiological characteristics and examined whether those characteristics were associated with deterioration during prolonged running.

This design can identify relationships between measurements. It cannot prove that 1 characteristic caused another.

For example, runners with greater leg strength may also have trained more consistently, accumulated more experience, or differed in several other ways. The study could not fully separate those possibilities.

Participants

Who took part?

The final analysis included 33 runners: 18 men and 15 women. Their average age was 29.8 years.

The researchers classified 15 participants as competitive runners and 18 as recreational runners. The competitive runners were Tier 3 or higher under an established athlete-classification framework, while the recreational runners were Tier 2.

All the participants ran at least 3 times per week and had completed a half marathon or an event of similar duration during the previous 12 months. The recreational runners had completed a half marathon in under 2 hours or achieved an equivalent result in triathlon, ultrarunning, or orienteering.

The participants had to be healthy and free from musculoskeletal injuries. The researchers also completed health screening and resting electrocardiography.

Methods

What did the researchers do?

Who? 33 trained runners
What? Laboratory testing before and after prolonged running
How long? 3 visits and a 138-minute prolonged run

The runners attended the laboratory on 3 occasions. The visits were separated by at least 48 hours and no more than 10 days.

Before each test, the researchers asked the runners to avoid caffeine for 12 hours. They also avoided alcohol and intense exercise for 24 hours and used the same footwear and similar clothing.

During the 1st visit, the researchers measured body composition, peak fat oxidation, and performance in a maximal anaerobic running test. They also measured the highest blood lactate concentration after that test.

During the 2nd visit, the runners completed treadmill tests to measure maximal oxygen uptake, maximum speed during the maximal test, and speed at the 1st and 2nd ventilatory thresholdsPoints during exercise where your breathing suddenly ramps up. It’s your body’s signal that the effort level has shifted and you’re relying more on faster energy sources. They can be used as points to set training zones..

The ventilatory thresholds mark changes in breathing that help estimate transitions between exercise-intensity zones.

During the 3rd visit, the runners completed the physiological-resilience test. This involved four short incremental treadmill tests and three 30-minute moderate-intensity running bouts.

The prolonged-running portion lasted 138 minutes. The runners then rested for 10 minutes before completing another maximal test.

Across the prolonged-running portion, the runners averaged about 89% of their speed at the 1st ventilatory threshold. Their oxygen uptake averaged about 90% of the oxygen uptake measured at that threshold.

The competitive runners covered an average of 28.4 km. The recreational runners covered 22.3 km because everyone ran for the same duration rather than the same distance.

The participants could drink water but could not consume external energy during the running protocol. Before the final maximal test, they rinsed their mouths with 200 mL of a 6% carbohydrate solution and spat it out.

The researchers measured changes in maximal oxygen uptake, maximum treadmill speed, speed at both ventilatory thresholds, running economy, maximum leg-press force, and countermovement-jump height.

The researchers expressed running economy as the energy required to cover 1 km. A higher energy cost meant that economy had worsened.

Main findings

What did the study find?

Maximum treadmill speed Decreased by 6.4%
Running economy Energy cost increased by 5%
Maximal oxygen uptake Decreased by 2.3%

Across the 33 runners, the group averages changed significantly for every measured performance and physiological outcome.

Maximum treadmill speed decreased by 6.4%. This was the largest standardised decline reported in the study.

Speed at the 2nd ventilatory threshold decreased by 5.5%. Speed at the 1st ventilatory threshold decreased by 4.4%.

Maximal oxygen uptake decreased by 2.3%.

The energy cost of running increased by 5%, meaning that running economy worsened. The runners required more energy to cover the same distance late in the test.

Maximum leg-press force decreased by 4.6%. Countermovement-jump height unexpectedly increased by 4.5%.

These were average changes. Individual responses varied, and not every runner deteriorated in every outcome.

Aerobic fitness and maximum treadmill speed

A higher maximal oxygen uptake was associated with a smaller decline in maximum treadmill speed after prolonged running.

The association was statistically significantEvidence that a result is unlikely to be due to chance under a “no effect” model (or null hypothesis). Statistical significance is often judged by a p-value below 0.05 to flag that “something” is going on, but not how big or important that “something” is. One statistically significant result doesn’t mean proof; replication is needed. And, a statistically significant result doesn’t necessarily indicate clinical significance. but modest. Maximal oxygen uptake therefore explained only part of the considerable differences between runners.

A lower peak blood lactate concentration after the maximal anaerobic test was also associated with a smaller decline in maximum treadmill speed.

The authors suggested that a lower blood lactate value might indicate lower glycolytic capacity relative to aerobic capacity. It might also reflect a greater proportion of fatigue-resistant muscle fibres.

The researchers did not measure muscle-fibre type, so this explanation remains speculative.

Aerobic fitness and the 1st ventilatory threshold

Runners with higher maximal oxygen uptake, faster threshold speeds, and a faster maximum treadmill speed generally experienced a smaller decline in speed at the 1st ventilatory threshold.

The associations ranged from modest to moderate.

The strongest association was between the initial speed at the 2nd ventilatory threshold and the preservation of speed at the 1st threshold.

These findings suggest that runners with greater aerobic fitness tended to preserve their moderate-intensity threshold speed better.

They do not show that improving maximal oxygen uptake or threshold speed will necessarily cause better resilience.

None of the measured baseline characteristics was significantly associated with the deterioration in speed at the 2nd ventilatory threshold.

Leg strength and running economy

Greater maximum force during the isometric leg press was associated with a smaller deterioration in running economy.

The association was moderate.

The authors suggested that stronger runners may need to use a smaller proportion of their maximum force with each stride. This could reduce the need to recruit less-efficient muscle fibres as fatigue develops.

The authors also proposed that greater strength might help preserve the elastic properties of the muscle-tendon system. The researchers did not measure muscle recruitment or tendon stiffness, so these remain possible explanations rather than confirmed mechanisms.

Runners with worse economy while fresh also tended to show less deterioration.

This may partly reflect a baseline-value effect. A runner who starts with unusually good economy has more room for that measurement to worsen, while someone starting with poorer economy has less room to fall.

Fat oxidation and resilience

The competitive runners had higher peak fat oxidation than the recreational runners. They also reached peak fat oxidation at a higher relative exercise intensity.

Despite those differences, neither peak fat oxidation nor the intensity at which it occurred was significantly associated with any measured resilience outcome.

This does not prove that fat oxidation is irrelevant during long runs. The fat-oxidation test involved walking rather than running, and the sample may have been too small to identify weaker relationships.

The participants also consumed no external energy during the protocol. Because carbohydrate intake can affect fatigue, this limits how closely the test reflects normal race practice.

Competitive and recreational runners

The recreational runners experienced a larger decline in speed at the 1st ventilatory threshold.

The competitive runners’ threshold speed decreased by about 2.6%. The recreational runners’ threshold speed decreased by about 5.9%.

The difference was statistically significant.

The competitive runners unexpectedly experienced a larger deterioration in running economy. Their energy cost increased by about 6.3%, while the recreational runners’ energy cost increased by about 3.8%.

The competitive runners ran faster, covered more distance, and lost more body mass during the fixed-duration protocol.

Because running economy was expressed relative to body mass, the greater body-mass loss affected the apparent change among the competitive runners.

The researchers completed an additional analysis using absolute energy expenditure. That analysis found no clear difference between the groups, weakening the argument that the competitive runners genuinely had poorer economy resilience.

The groups did not differ significantly in the deterioration of maximal oxygen uptake, maximum treadmill speed, or speed at the 2nd ventilatory threshold.

The authors concluded that physiological resilience probably depends on several physiological systems. Aerobic fitness appeared most relevant to preserving some running-speed measures, while leg strength appeared relevant to preserving running economy.

What helps my confidence in the findings?

The strengths

  • The researchers studied trained runners rather than an unrelated sport or an untrained population.
  • The sample included 18 men and 15 women.
  • The researchers used detailed and largely standardised laboratory procedures across 3 visits.
  • The prolonged-running test produced meaningful fatigue and covered distances relevant to endurance running.
  • Two experienced researchers independently assessed the ventilatory thresholds in a blindedBlinding is when people in a study don’t know which treatment they’re getting. It stops expectations or beliefs (from patients or researchers) from skewing the results. “Single-blind” means participants don’t know; “double-blind” means participants and researchers don’t know; “triple-blind” means that the participants, researchers, and data analysts are kept in the dark. The goal is simple: fair tests and trustworthy findings. manner.

What limits my confidence in the findings?

The limitations

  • Only 33 of the 45 recruited runners completed the full study, and the sample was small for examining numerous associations.
  • The authors provided a sample-size rationale based on previous studies but did not report a conventional power calculationA power calculation is a way to figure out how many people or data points you need in a study so you can reliably spot a real effect if it exists. It balances four things: the size of the effect you care about, how much random variation there is, how strict you are about false alarms, and how likely you want to be to detect the effect. In plain terms: it helps you avoid running a study that’s too small to be useful or so big that it wastes time and money. for the correlations or group comparisons.
  • The researchers tested many correlations without reporting an adjustment for multiple comparisonsMultiple comparisons happen when you test many hypotheses or look at many outcomes in the same data set. Each test has some chance of finding a difference just by luck (this is a “false alarm”, i.e., a false positive). When you do lots of tests, those chances add up. That means you’re more likely to find something that looks “significant” but is actually just noise., increasing the possibility of chance-positive findings.
  • The cross-sectional design cannot show that improving aerobic fitness or strength causes better resilience.
  • The fixed-duration treadmill protocol exposed the competitive runners to a greater distance and total workload and did not recreate the terrain, intensity, feeding, or environmental demands of most races.

Funding and conflicts

Who funded the study?

The Finnish Sports Research Foundation funded the study.

The authors declared no conflicts of interestA conflict of interest happens when a person or group has a personal, financial, or professional interest that could influence their judgment. It does not always mean they did something wrong. But it can create bias or make others question whether the decision or result is fully fair and trustworthy.. The funder was not a manufacturer of running equipment, supplements, or another product tested in the study.

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