REF-423 · Passfield & Doust, 2000 · Medicine & Science in Sports & Exercise, Vol. · Paper · PubMed

Changes in cycling efficiency and performance after endurance exercise

Early demonstration that prolonged riding lowers 5-min power together with gross efficiency

Blimited evidenceMeasured on trained to highly trained athletesWritten before October 2026, being re-checked

Participants

n=10 endurance-trained cyclists (n from the full text; not checked against the abstract — the abstract gives no sample size and describes them only as "endurance trained cyclists").

Protocol

Two experiments, each starting with a controlled warm-up: in EXP1 subjects did as much work as they could in 5 min (performance test); in EXP2 they did a maximal 30-s sprint

Next came roughly 60 min of riding at roughly 60% VO2peak, or the same length of rest as the control, after which the warm-up was repeated, followed again by the 5-min performance test or 30-s sprint test

Gross efficiency calculated from expired gas collected over the last minute of each warm-up period

Key Findings

Average 5-min performance power output was significantly reduced after the ~60-min ride in EXP1 (by 12 W)

In EXP2 both peak and mean 30-s sprint power were significantly lower after the ride (by 26 W and 35 W respectively)

Gross efficiency decreased significantly with the exercise in both experiments

Shifts in gross efficiency tracked how 5-min performance shifted (r = 0.91, P < 0.01), yet showed no correlation with changes in 30-s sprint power, mean or peak

Authors' conclusion: the loss of 5-min performance was related to the fall in gross efficiency brought on by the exercise

Mechanism (proposed)

Inference, not tested: the coupling of efficiency loss with 5-min power loss (r = 0.91) points to a metabolic/efficiency cost of prior work behind the mid-duration decline; the 30-s sprint decline was not tied to efficiency, so a different mechanism is implied for very short efforts

The authors did not have the "durability" vocabulary; they framed the phenomenon as efficiency change after endurance exercise

Practical Application

In endurance-trained cyclists, about 60 min of riding at about 60% VO2peak cut 5-min maximal power by 12 W and 30-s sprint peak/mean power by 26/35 W versus a rest control, and gross efficiency fell in both experiments; the fall in efficiency tracked the fall in 5-min power (r = 0.91) but not the sprint loss — even a moderate hour of riding measurably lowers the power available afterwards, and the mechanism for a 5-min effort differs from a sprint.

The paper does not test whether rested VO2max or threshold predicts the decline — the later "durability is independent of the lab profile" claim rests on REF-196, and the opposite finding on REF-424; this paper only shows that the decline exists and travels with efficiency.

Inference, not tested: if a key 5-min effort comes after hours of riding, training and testing it fatigued is the specific stimulus; a fresh 5-min test overstates what will be available late.

Limitations

Small within-subject experiments (n=10 per the full text; not checked against the abstract), trained cyclists

Single prior-exercise dose (~60 min at ~60% VO2peak); longer or harder rides untested

Whether rested physiological measures predict the decline was not tested

Efficiency measured only over the last minute of a warm-up; gas-analysis methods of 2000

How this entry was checked and changed

Why this level

regraded 2026-09-27 from B+: within-subject experiments, n=10, no predictor analysis

Content correction 2026-09-27

"~1 h near LT2 (~85-90% VO2max)" -> approximately 60 min at approximately 60% VO2peak, with a rest control condition.

"5-min power fell ~5-8% (range -2% to -12%)", "GE fell ~2-3% absolute (~5-10% extra O2 cost)" -> deleted; the abstract reports 5-min power -12 W, 30-s sprint peak/mean -26/-35 W, and a significant GE decrease without a percentage.

"Rested VO2max / LT2 did NOT predict the decline" -> deleted; no such analysis is in the abstract. Added the actual result: the GE change correlated with the 5-min power change (r = 0.91) but not with sprint power.

"VO2max ~60-65, recreationally trained, male" -> deleted; the abstract says "endurance trained cyclists", no VO2max or sex. Level B+ -> B; Tier and Sport lines added; the REF-117 cross-reference (low-cadence review, not running economy) removed.

2026-09-28: PMID 11079527 belonged to an unrelated paper; replaced with 11079525, the PubMed record for this entry's own DOI.

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).