REF-986 · Sondermann et al., 2026 · International Journal of Sports Physiology and Performance, pp. 1-15 · Paper · PubMed

Fractional Utilization of V̇O2max

A Key Performance Determinant in Endurance Sports?

C+thin evidenceMeasured on a mixed groupWritten before October 2026, being re-checked

A narrative overview of the literature on fractional utilization of VO2max (%VO2max) — at the lactate threshold (LT) or at competition intensity — as one of the classic performance-determining variables in endurance sport, and of whether it can be improved through training.

The authors note that the importance of VO2max and of efficiency/economy has been confirmed repeatedly, while the evidence on %VO2max is less conclusive.

Out of the 35 studies assessing the relationship between %VO2max and performance, only a few confirm a substantial relationship; this holds both for %VO2max at a physiological landmark such as LT and for %VO2max at a competition-specific intensity. There is limited evidence that %VO2max can be systematically altered through training in trained athletes.

The authors conclude that %VO2max does not seem to be a strong predictor of endurance performance and that practical recommendations on how to improve it via training cannot currently be given.

Participants

No participants of its own. The review covers 35 studies assessing the relationship between %VO2max and performance; the number of studies on trainability, and the sports, sexes and competitive levels of the athletes, are not given in the abstract.

Protocol

Design: narrative review ("a narrative overview of the current literature"). No search strategy, inclusion criteria or quality appraisal are described in the abstract.
Two questions: (1) is %VO2max — at LT or at a competition-specific intensity — related to endurance performance; (2) can %VO2max be improved through training.
Nature of the underlying evidence: studies of the relationship between %VO2max and performance (between-athlete association); training interventions of varying design.

Key Results

Out of the 35 studies assessing the relationship between %VO2max and performance, only a few confirm a substantial relationship. The count of "a few" is not given in the abstract.
This holds for %VO2max at a specific physiological landmark such as LT and for %VO2max at a competition-specific intensity.
Limited evidence that %VO2max can be systematically altered through training in trained athletes.
Methodological differences in the assessment of VO2max, LT and endurance performance across the included studies, and variation in the training interventions, confound the interpretation.
Authors' conclusion: %VO2max at LT or at competition intensity does not appear to predict endurance performance strongly; no practical advice on raising %VO2max through training can be offered yet; they encourage researchers to gather and publish %VO2max data.

Practical Application

"My threshold is a low percentage of my VO2max — should I do threshold work to raise that percentage?" A narrative review (35 studies of the %VO2max-performance relationship, endurance athletes, between-athlete evidence) found that only a few studies confirm a substantial relationship between fractional utilization and performance, and that evidence it can be systematically changed by training in trained athletes is limited — the authors state that no training recommendation for raising it can currently be given. A low ratio is therefore not, by itself, a reason to choose a threshold block.
What it does not say: that threshold training is useless, or that the ratio never moves. "Limited evidence" and "only a few studies" describe the state of the literature; the abstract reports no effect size and names methodological differences as a confounder.
Inference, not tested here: because the ratio is VO2 at threshold divided by VO2max, it can rise when the ceiling falls and fall when the ceiling rises; a change in the ratio alone does not show which term moved.
Not from this paper: individual entries in the base report the fraction moving in specific groups — after added heavy strength training in female cyclists (REF-073) and across a season in elite road cyclists (REF-095). Those are single studies; this review's summary of the whole literature is that such evidence is limited.

Limitations

Narrative review: no search method, inclusion criteria or risk-of-bias assessment in the abstract; conclusions are qualitative.
"Only a few" and "limited evidence" are not quantified; no effect sizes, sports or athlete levels are given in the abstract.
The relationship studies are associations between athletes; they cannot show what happens within one athlete who trains.
The authors themselves name methodological differences in how VO2max, LT and performance were assessed as confounding the interpretation.
Online ahead of print; written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

narrative review without a stated systematic method; the conclusion is the authors' reading of a heterogeneous literature, not a pooled estimate

Content correction 2026-09-27
2026-10-02: aligned with the rewritten SYNTH-42 (missing stimulus, one lever per block, level C+): cross-reference description — the ratio is a note there, no longer a decision axis.