REF-753 · Capostagno B, Lambert MI, Lamberts RP — 2014 · International Journal of Sports Physiology and Performance, · Paper · PubMed
Cyclists whose four HIT sessions over two weeks were timed by a submaximal test improved their 40-km time trial by 48 ± 42 s, against 8 ± 45 s for cyclists on a fixed schedule
A large effect size in a small two-group study
Protocol
Two groups of male cyclists each completed four high-intensity interval sessions over two weeks. The structured group (n = 8) followed a predetermined schedule; the flexible group (n = 7) had the timing of its HIT sessions prescribed from LSCT results (REF-752).
Key Findings
40-km time-trial improvement: flexible 48 ± 42 s vs structured 8 ± 45 s — reported as a large difference by effect size.
Heart-rate recovery tended to increase in the flexible group and stayed unchanged in the structured group.
The same total HIT dose was delivered in both groups; what differed was when each session happened.
Practical Application
Use a submaximal test to decide whether today is the day for the hard session, not how many watts it should be. In this study the test moved the timing of HIT sessions; the sessions themselves were not rescaled, so evidence for trimming interval targets from a warm-up test is not in this base.
When the test says "not today", postpone the key session and ride easy, keeping the block's total dose — the flexible group did the same four sessions as the fixed group.
Expect the benefit over two weeks to be small in absolute terms and noisy between athletes (SDs of 42-45 s around means of 8 and 48 s).
Limitations
n = 15 across two groups; allocation and baseline VO₂max differed (58.4 vs 53.9 mL/kg/min); conclusions rest on effect sizes rather than significance.
Two weeks, men only, one research group.
The abstract does not specify the exact decision rules used to time sessions; they are not reproduced here.
How this entry was checked and changed
Content correction 2026-09-27
Resync 2026-09-28: Cross-ref pointed 'HRV-guided training' at REF-361 (Plews review) -> REF-362 (Javaloyes 2019 HRV-guided RCT).