Training twice every second day with low glycogen versus once daily for 3 weeks in well-trained cyclists (pair-matched, randomised): interval power was lower (297 vs 323 W), the time trial improved ~10% in both groups, and fat oxidation rose with the stacked schedule
Fourteen well-trained cyclists were pair-matched and randomised to train once daily (alternating a 90-min aerobic ride and an interval session) or twice every second day (aerobic ride, then intervals 1 h later) for 3 weeks: nine of each session in both groups.
Participants
14 well-trained cyclists, pair-matched, randomised to HIGH or LOW glycogen training.
Protocol
Nine aerobic sessions (90 min at 70% VO2max) and nine interval sessions (8 × 5 min, 1-min recovery) in 3 weeks.
HIGH: once daily, alternating. LOW: twice every second day, intervals 1 h after the aerobic ride.
Before and after: resting biopsy, metabolic measures during steady cycling, a time trial.
Key Results
Power during the interval sessions was 297 ± 8 W in LOW against 323 ± 9 W in HIGH (P < 0.05); time-trial performance improved by ~10% in both groups.
Fat oxidation during steady cycling rose in LOW (26 → 34 µmol/kg/min, P < 0.01); muscle-derived triacylglycerol oxidation rose in LOW (16 → 23); β-HAD protein increased with low-glycogen training.
Authors' conclusion: training with low glycogen reduced training intensity and was no more effective for performance.
Practical Application
Doing two sessions back to back every other day bought more fat oxidation and cost about 26 W in the interval session, with the same ~10% time-trial gain as training once a day. If the intervals matter, do not put them straight after a long steady ride as a matter of routine.
Whether that holds for events of several hours was not tested.
Limitations
n=14, 3 weeks; one time trial whose length is not given in the abstract.
Clustering and low glycogen are confounded by design.
Nothing on durability or long-event performance.
How this entry was checked and changed
Why this level
randomised, but n=14 and 3 weeks