REF-697 · Bangsbo, Kissow & Hostrup, 2025 · Scandinavian Journal of Medicine & Science in Sports, · Paper · PubMed · Free full text
Speed-endurance training improves performance in trained athletes across 20 s–60 min events, even with markedly reduced training volume and without a change in VO₂max
Key Findings
Speed endurance training (SET) = training at intensities above those eliciting VO₂max. Only studies of trained subjects and athletes were reviewed, grouped by event duration (20–60 s, 1–10 min, 10–60 min) plus repeated intense exercise (team sports), and by SET alone vs combined with aerobic or power/resistance training.
SET enhanced performance across all these event durations, even when training volume was markedly reduced.
The gains came without changes in VO₂max and were typically associated with better exercise economy and a greater capacity to handle muscle ionic shifts and counter exercise-induced falls in pH.
full text, checked 2026-09-27: two sub-types — "production" (repeated 10–40 s bouts with long recovery, e.g. 30 s / 3 min) and "maintenance" (5–120 s bouts with shorter recovery, e.g. 1 min / 1 min). Reported adaptations include higher muscle Na⁺–K⁺ pump subunits and FXYD1, NHE1, MCT1, SERCA and the glycolytic enzyme PFK.
full text, checked 2026-09-27: muscle oxidative enzymes mostly did not change, with decreases in CS / COX IV in some SET-alone studies and increases in one study where 30-s sprints were embedded in moderate-intensity cycling. For events over 60 min, few studies exist (elite cyclists: no change in performance with reduced volume) and the authors draw no firm conclusion beyond "no negative effect".
full text, checked 2026-09-27: 6 sprint repetitions per session were as effective as 12 in elite cyclists, and twice-weekly SET as effective as four times weekly in familiarised runners — high SET volume appeared unnecessary.
Practical Application
Bangsbo et al.'s review of trained athletes: speed-endurance work (above VO₂max intensity) improved performance in 20–60 s, 1–10 min and 10–60 min events, even with markedly reduced total volume, with no change in VO₂max — gains typically associated with better economy and ion/pH handling — worth periods of SET for anyone racing efforts in that range, alone or alongside aerobic or strength training.
Inference, not tested: SET does not appear to cost aerobic fitness in these studies, but it also does not build the oxidative machinery — keep the low- and moderate-intensity base alongside it rather than replacing it.
Inference, not tested: do not expect SET to move performance beyond ~60 min; the review found too few studies to say.
Limitations
Narrative review, not a systematic review or meta-analysis — no pooled effect size; heterogeneous intervention studies of varying dose and design, many small.
Muscle oxidative-marker findings are mixed (mostly unchanged, some decreases, one increase); the review does not show that SET builds the aerobic engine.
Evidence for events over 60 min is sparse.
How this entry was checked and changed
Content correction 2026-09-27
Type "systematic (vote-counting) review" -> narrative review (the abstract says "this review"; the paper uses a keyword search without systematic method).
Removed invented specifics: SET as "20–60 s all-out with 2–5 min recovery" (full text defines production 10–40 s / maintenance 5–120 s bouts), "largest gains 1–10 min", the lactate / Pi / K⁺ / Ca²⁺ fatigue paragraph, and the >60 min fuel/thermoregulation explanation — none is in the abstract or the paper's text.
"Mitochondrial markers IMPROVE when SET sits inside a program with low/medium intensity" -> full text: oxidative enzymes mostly unchanged, some decreases with SET alone, one increase with sprints embedded in moderate cycling; "> 60 min unchanged" -> too few studies, no firm conclusion.
Protein adaptations, inclusion VO₂max and dose findings labelled as full text; aerobic-base advice labelled as inference; Sport "conditioning" -> "running, cycling, general".
Lines labelled "full text; not checked against the abstract" were checked against the open-access full text (PMC12203883): every number in them appears there; relabelled "full text, checked 2026-09-27".
Full text (checked 2026-10-12)
Runners doing 8–12 × 30‐s all‐out sprints with 3‐min rest 3–4 times a week for 4 weeks, with a 64% reduction in training volume, improved 30‐s sprint performance by 7% and exhaustive 1–3 min running by 19%–27% (full text).
Combining SET (8–12 × 30‐s sprints 2–3 times per week) with aerobic high-intensity training (4 × 4 min 1–2 times a week) and 30% less training lowered 10‐km time from 37.3 to 36.3 min (full text).
After 40 days of SET (10 sessions of 30‐s sprints) with a 30%–40% reduction in training volume, runners improved 10‐km performance by 2%–4%, with better running economy (full text).
Elite cyclists doing 6 × 30‐s sprints twice a week for 6 weeks (training lowered by 30%) improved a 20‐min time trial by 6%, while the 12-repetition group did not improve despite higher muscle Na+–K+ subunits and FXYD1 (full text).
The authors state that in some studies with moderately trained individuals SET increased V̇O2‐max, but in well-trained individuals no change in V̇O2‐max was observed; for example, 10–20–30 training increased V̇O2‐max by 6.4% (submaximal sprints) and 7.5% (maximal sprints) (full text).
Most of the tabled interventions were in male subjects; female participants appear only in a few studies (e.g. 25 F elite volleyball players, 14 M/4 F runners) (full text, Table 1).
On injury risk, the authors write that cycling makes injuries rare and running studies reported low overuse injury rates, but that larger, properly powered studies are needed (full text).