The Effects of Recovery Frequency On V[Combining Dot Above]O2, Muscle Deoxygenation, And Energy System Contribution During Intermittent Work
Bibliographic record
Abstract
PURPOSE: To compare the effects of inserting 3 s recovery periods during high-intensity continuous exercise at 25 s and 10 s intervals on: 1) energy system contribution, 2) the rates of adjustment of pulmonary oxygen uptake (V[Combining Dot Above]O2p) and muscle deoxygenation (HHb), and 3) the overall changes of V[Combining Dot Above]O2p and HHb. METHODS: Eleven recreationally active men (age: 24 ± 3 yrs; V[Combining Dot Above]O2max: 47.9 ± 4.7 mL·kg-1·min-1) reported to the laboratory on six separate occasions to complete two trials of three cycling exercise protocols: 1) a continuous protocol (CONT) consisting of 8 min of constant work rate exercise at an intensity corresponding to 60% of the difference between lactate threshold and V[Combining Dot Above]O2max (60); 2) an 8 min intermittent exercise protocol consisting of a series of 25 s work periods at 60 separated by 3 s recovery periods (25INT); and 3) an 8 min intermittent exercise protocol consisting of a series of 10 s work periods at 60 separated by 3 s recovery periods (10INT). All protocols began with a 4 min baseline of 20 W. During each trial, breath-by-breath gas-exchange measurements were collected using mass spectrometry and volume turbine and near-infrared spectroscopy was used to measure [HHb] of the vastus lateralis muscle. Arterialized-capillary blood samples (~5 μL) were taken from the index finger 6 min before and 2 min after all trials and analyzed for blood lactate concentration ([Lac-]). RESULTS: Post-exercise [Lac-] was greatest (p<0.05) in CONT (14.3 mM), followed by 25INT (10.2 mM, p<0.05) and 10INT (7.0 mM, p<0.05). More frequent recovery periods decreased (p<0.05) respiratory exchange ratio (CONT: 1.13; 25INT: 1.09; 10INT: 1.06), and end-exercise V[Combining Dot Above]O2p (CONT: 3.69 L·min-1; 25INT: 3.29 L·min-1; 10INT: 2.89 L·min-1). The mean V[Combining Dot Above]O2p from time 0 to 180 s, was reduced (p<0.05) as the frequency of recovery periods increased (CONT: 2.62 L·min-1; 25INT: 2.50 L·min-1; 10INT: 2.32 L·min-1). The rate of adjustment of [HHb] and [HHb] at end exercise did not differ amongst conditions (p>0.05). CONCLUSION: Increasing the frequency of 3 s recovery periods during continuous exercise reduced and increased the contribution of oxidative phosphorylation and substrate-level phosphorylation, respectively. This ultimately resulted in a slower rate of adjustment of V[Combining Dot Above]O2p and likely a reduction in microvascular blood flow to the working muscle.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".