REF-1506 · Hue et al., 2002 · Research Quarterly for Exercise and Sport · Paper · PubMed

Do brick blocks make the run off the bike faster?

In the one trial found, 12 triathletes, 6 weeks: overall cycle-run no better (3.3% vs 6.1%), transition plus first 333 m better (−11.2 vs −1.2 s). Small; not HYROX.

Main caveat: Read from the abstract only. Test, doses, group sizes and funding could not be checked.
limited, mixed evidenceMeasured on trained to highly trained athletes

Twelve competitive triathletes were randomised to 6 weeks of multicycle-run training (multiple short cycle-run sequences) or normal training. Baseline training stayed the same in both; only the high-intensity component differed, performed at or above 100% of maximal aerobic velocity.

Overall cycle-run performance rose in both, by 3.3 ± 1.4% with the blocks and 6.1 ± 1.7% with normal training, called similar by the authors, with the larger mean in the normal arm. The cycle-run change plus the first 333-m lap, termed the cycle-run transition, improved significantly more with the blocks: −11.2 ± 6.8 vs −1.2 ± 7.7 s.

The authors conclude that the blocks did not beat normal training overall but improved the transition, and suggest skill and physiological adaptations as reasons. Our reading: a small trial with a significant but narrow signal (no p-value in the abstract), on the segment closest to what was practised.

Protocol

Who: n = 12 competitive triathletes, randomised into two groups; sizes per group, sex and fitness not in the abstract.
Length: 6 weeks.
Intervention: multiple, short cycle-run sequences. Comparator: normal training. Baseline training identical; only the high-intensity component differed, performed at or above 100% of maximal aerobic velocity. Number of blocks, durations and rest are not in the abstract.
Outcomes: overall cycle-run performance; the cycle-run transition, defined as the cycle-run change plus the first 333-m lap. The test's ride length and run distance are not in the abstract.
Funding and interests: not in the abstract.

Key Results

OutcomeMulticycle-runNormal trainingAuthors' statement
Overall cycle-run performance, rise3.3 ± 1.4%6.1 ± 1.7%"similar"; no greater improvement with the blocks
Cycle-run change + first 333 m−11.2 ± 6.8 s−1.2 ± 7.7 ssignificantly greater with the blocks

No p-values, confidence intervals or individual data in the abstract. The overall means favour the normal arm; the abstract calls them similar, without saying how large a difference was tested.

Mechanisms

Measured: change in overall cycle-run performance and in the transition segment.
Authors' interpretation: the blocks "may help" triathletes develop greater skill and better physiological adaptations in the transition. The abstract reports no measurement of either.
Inference: the segment includes the physical change of discipline, so part of the gain can be practice at the change itself and not fitness; the abstract does not separate them.

Practical Application

Do brick blocks make the run off the bike faster? In the one trial found, 12 triathletes, 6 weeks: overall cycle-run no better (3.3% vs 6.1%), transition plus first 333 m better (−11.2 vs −1.2 s). Small; not HYROX.
Good for: the honest answer on compromised-running practice. It may sharpen the opening of the run; it did not beat normal training on the whole effort, and the blocks were themselves high-intensity (at or above 100% of maximal aerobic velocity), so this is no evidence for easy bricks (our reading).
Not good for: promising a faster race from bricks, or scaling seconds to another event.
HYROX (transfer, inference): not from this paper; the base's own practice: a weekly station-to-run session from about 8 weeks out (SYNTH-71). This trial is the nearest controlled analogue for the idea, in triathletes off a bike, and points only to the opening of the run.

Limitations

Read from the abstract only. Test, doses, group sizes and funding could not be checked.
n = 12 over 6 weeks. The null on overall performance is underpowered and its means point the other way; the positive result is a sub-segment with SDs near the size of the effect, and the abstract does not say whether it was the planned main outcome.
One trial. Described as the only brick-practice trial on the search behind this batch, not as the only one that could exist.
Dated and narrow. 2002, one group of competitive triathletes; no women named in the abstract.
How this entry was checked and changed
Why this level

(from the abstract) — parallel RCT with n = 12 (rubric B), one step lower because key methods are missing from the abstract: the cycle-run test, the group sizes, the block doses and the between-group p for the overall result are not given. Subscription article; the only repository record (HAL hal-00720124) is a notice without a file