REF-1518 · Etxebarria et al., 2014 · Journal of Sports Sciences · Paper · PubMed

Does a fresh run test show running off the bike?

Not directly, the authors say: in 9 triathletes, run physiology worsened after 1 h cycling, more after surges (4 mM speed 0.6 ± 0.9 km/h lower vs steady; limits cross zero). Submaximal.

Main caveat: Read from the abstract only. Order, recovery, test protocol, fresh-run results and funding could not be checked.
limited, mixed evidenceMeasured on trained to highly trained athletes

Nine well-trained male triathletes did a submaximal incremental run under three conditions: with no prior exercise, after 1 h of cycling at 65% of maximal aerobic power held constant, and after the same hour with variable power, using multiple 10-90 s efforts at 40-140% of maximal aerobic power.

During cycling, ventilation (22% ± 14%), blood lactate (179% ± 48%) and RPE (7.3% ± 10.2%) were higher in the variable ride. At the start of the run lactate was 64% ± 61% higher after variable than after constant cycling, which the authors say decreased running velocity at the 4 mM lactate threshold by 0.6 ± 0.9 km/h.

They conclude that physiological responses to incremental running are negatively affected by prior cycling and more so by variable cycling. Our reading: a small comparison that supports not reading race pace off a fresh test.

The size given for variable vs constant has confidence limits that include no difference, and the abstract gives no figure for fresh vs after-cycling running.

Protocol

Who: n = 9 well-trained male triathletes.
Conditions: (1) no prior exercise; (2) 1 h cycling at 65% of maximal aerobic power, constant; (3) 1 h at the same 65% mean, variable, with 10-90 s intermittent efforts at 40-140% of maximal aerobic power.
Test: submaximal incremental run after each condition. Stage lengths, speeds, the gap after cycling and the order of conditions are not in the abstract.
Statistics: mean ± 90% confidence limits.
Funding and interests: not in the abstract.

Key Results

Comparison: variable vs constant cyclingMean ± 90% confidence limits
Ventilation during cycling22% ± 14% higher
Blood lactate during cycling179% ± 48% higher
RPE during cycling7.3% ± 10.2% higher
Blood lactate at the start of the run64% ± 61% higher
Running velocity at 4 mM lactate0.6 ± 0.9 km/h lower

The RPE and running-velocity limits include no difference (our reading of the ± values); the authors call the physiological changes substantial and do not state the size for fresh vs after-cycling running in the abstract.

Mechanisms

Measured: more ventilation, lactate and RPE in the surging ride, and more lactate going into the run.
Authors' interpretation: the higher lactate after variable cycling decreased running velocity at the 4 mM threshold, so testing and training should account for the cost of race-like cycling.
Inference: a fixed 4 mM marker can read lower just because the athlete began with more lactate on board. The test thus partly shows what came before, and not only a lower running capacity. It does not measure race speed; REF-831, from the same group, tests the run itself.

Practical Application

Does a fresh run test show running off the bike? Not directly, the authors say: in 9 triathletes, run physiology worsened after 1 h cycling, more after surges (4 mM speed 0.6 ± 0.9 km/h lower vs steady; limits cross zero). Submaximal.
Good for: the reason to set paces from running off prior work, not only from a fresh test. Direction only.
Not good for: a correction factor. Nothing in this abstract converts a fresh threshold to an after-work pace, and 0.6 km/h does not transfer to any other athlete or event.
For a performance number: REF-831 found a 9.3-km run 42 ± 37 s slower after a variable ride than a steady one in 12 men.
HYROX (transfer, inference): not from this paper; the base's own practice: set run splits from off-station pace (SYNTH-71). This is a cycling analogue, not a station test.

Limitations

Read from the abstract only. Order, recovery, test protocol, fresh-run results and funding could not be checked.
n = 9 men. Wide limits: 64% ± 61% for lactate, 0.6 ± 0.9 km/h for velocity.
A marker. Speed at 4 mM from a submaximal test, not performance.
The title goes further than the numbers in the abstract: "does not directly replicate" is supported in the abstract by words, not by a figure for fresh running.
How this entry was checked and changed
Why this level

(from the abstract) — crossover n = 9 (rubric B: <15), one step lower: the outcome is a physiological marker, not performance; order, run protocol and fresh-run numbers are missing from the abstract. Subscription article; OpenAlex lists no open copy