Caloric Unit Cost As A Measure Of Running Economy In Trained Distance Runners
Bibliographic record
Abstract
Running economy (RE) has been typically defined in the literature as the rate of oxygen use to run a submaximal velocity, usually measured in ml O2·kg-1·min-1 or as an O2 unit cost (OC, ml O2·kg-1·km-1). However, measuring RE in this way may not reflect true energy cost because the caloric equivalent of oxygen changes with substrate. A more appropriate measure of RE may be to express it as a caloric unit cost (CC, kcal·kg-1·km-1). PURPOSE: To compare RE across three different submaximal velocities expressed as OC and CC in a group of highly-trained male distance runners. METHODS: 18 highly-trained male distance runners (24±4yrs, 177±7cm, 68±7kg; VO2max = 66±5ml·kg-1·min-1) completed a RE test consisting of 5 minutes at 75, 85 and 95% of velocity corresponding to lactate threshold (vLT). RE was measured using a metabolic cart and expressed as ml·kg-1·km-1 and kcal·kg-1·km-1. CC was calculated using the steady-state VO2 and caloric equivalent of oxygen uptake from RER over the same period. RESULTS: Average vLT was 260±31 m·min-1. Average OC was 223±24, 218±16 and 222±14 ml·kg-1·km-1 at 75, 85 and 95% vLT, respectively. Average CC was 1.06±0.09, 1.08±0.08 and 1.11±0.07 kcal·kg-1·km-1 across the three submaximal velocities. There was no difference in OC across velocities, whereas CC increased significantly with velocity (p<0.001). CONCLUSION: This study demonstrates that CC was more sensitive to changes in relative workload compared to OC. It is proposed that expressing RE as CC is a more appropriate expression of a runner's actual energy cost to cover a given distance. Supported by NSERC Canada.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".