After stopping training, VO2max fell 7% in 21 days and stabilised 16% below the trained value by day 56; oxidative enzymes halved in about 12 days, but capillaries did not fall
Seven endurance-trained people, 84 days of inactivity
Participants
n=7 endurance exercise-trained subjects, studied 12, 21, 56 and 84 days after stopping training; 8 sedentary never-trained controls.
Protocol
Measurements at 12, 21, 56 and 84 days after complete cessation of training: VO2max, exercise stroke volume and a-vO2 difference, and muscle capillarization and oxidative enzymes (citrate synthase, succinate dehydrogenase); sedentary controls measured for comparison.
Key Findings
VO2max declined 7% in the first 21 days of inactivity and stabilised after 56 days at 16% below the trained value.
After 84 days it was still higher than in the sedentary controls (50.8 vs 43.3 ml/kg/min), mainly through a larger a-vO2 difference.
Exercise stroke volume declined early to control levels; the early VO2max loss tracked stroke volume, the later loss the a-vO2 difference.
Citrate synthase and succinate dehydrogenase fell with a half-time of ~12 days and stabilised 50% above sedentary; capillarization did not decline and stayed 50% above sedentary.
Practical Application
When training stops completely, VO2max falls ~7% in three weeks and ~16% by eight, the first loss coming from stroke volume and oxidative enzymes halving in about 12 days, while capillaries hold (Coyle 1984, n=7) — a break of a few weeks costs real fitness, but not all of it.
What keeps it during a SMALLER load, rather than none, is in REF-374: keep the intensity, reduce frequency only moderately and cut the volume.
Not from this paper; the base's own practice: two short quality sessions a week are a reasonable floor during a busy week.
Limitations
n=7, no training-maintenance arm: it describes stopping, not reducing, training.
Full text not read; everything above is from the abstract.
How this entry was checked and changed
Why this level
small uncontrolled pre-post (n=7)
Content correction 2026-09-27
DOI 10.1152/jappl.1984.57.6.1857 attached for the entry's own citation (Coyle et al. 1984, J Appl Physiol 57(6):1857-1864 — exact match); identified by a search and attached with the owner's explicit OK (2026-09-27).
The paper studies complete cessation of training, not maintenance doses; the entry is now re-anchored to what it shows (detraining time course), and reduced-training maintenance stays with REF-374. The byline's second name (Ekblom & Gjessing) had no identifiable source and was dropped. Level C+ -> B.
Protocol section added from the abstract.
2026-10-01: cross-reference repointed from a merged framework to the one that replaced it (SYNTH-01→31, 05→34, 09→70, 12/15→32, 19→26).