Mechanisms for Increases in V˙O2max with Endurance Training in Older and Young Women
Bibliographic record
Abstract
PURPOSE: To examine the time course and mechanisms of cardiorespiratory fitness adaptation to training in older (O) and young (Y) women. METHODS: A total of six O (69 ± 7 yr) and eight Y (25 ± 5 yr) women were examined before training and after 3, 6, 9, and 12 wk of training. Training was performed on a cycle ergometer three times per week for 45 min at ∼70% of V˙O2max. RESULTS: V˙O2max (mL·kg(-1)·min(-1)) increased within 3 wk, with further changes observed at weeks 6 and 9 in both O (17% ± 14%) and Y and also posttraining (12 wk) in Y (22% ± 6%, P < 0.05). Maximal cardiac output (Q˙max, open-circuit acetylene) and stroke volume increased only in Y after 9 wk of training (P < 0.05). Age × testing time interactions in maximal arterial-venous O2 difference (a-vO2diff) after 6 wk of training revealed a greater dependence on a-vO2diff in O compared with Y (P < 0.05); ∼65% of the change in V˙O2max from pretraining to posttraining was explained by a widened maximal a-vO2diff in O compared with almost equal increases in Q˙max and maximal a-vO2diff in Y. The early adaptations (first 3 wk) in O relied exclusively on a nonsignificant increase in Q˙max, whereas Y depended on a widened maximal a-vO2diff. Later changes in V˙O2max were explained exclusively by an improved maximal a-vO2diff in O and a larger Q˙max in Y. CONCLUSIONS: O and Y women displayed a different time course of training adaptation in V˙O2max, with Y (after an initial improvement in maximal a-vO2diff) depending more on changes in Q˙max and O mostly relying on a widened maximal a-vO2diff.
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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 | 0.000 |
| 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".