Prolonged Exercise Training does not Preserve Mitochondrial Enzyme Activity in Senescent Rats
Bibliographic record
Abstract
Skeletal muscle aerobic function (VO 2max ) and mitochondrial oxidative capacity decline with aging, particularly in senescence (SEN). Since exercise training improves muscle VO 2max and oxidative capacity in young adult skeletal muscle, our objective was to determine if treadmill training from late middle age (LMA) into SEN would minimize the declines in skeletal muscle aerobic function and oxidative capacity seen in SEN. 62 male rats at late middle age (29 mo) were randomly separated into control and exercise groups. Exercise consisted of 60 m/day treadmill running, 5 d/week for 7 weeks and then decreased to 4 d/week for a total of 5 and 7 mo (until 34 and 36 mo of age respectively). Although running capacity was significantly higher in the trained groups (13% at 34 mo and 21% at 36 mo), muscle VO 2max at matched muscle O 2 delivery was not significantly greater in the trained groups compared to sedentary controls at either age. Similarly, citrate synthase and cytochrome oxidase activity in the plantaris, soleus and the heart muscle were not different in the trained vs the sedentary groups, suggesting no benefit of training for muscle oxidative capacity. The superior exercise capacity suggests a better overall level of function of the senescent rats; however, contrary to our hypothesis and prior observations in LMA rats, treadmill exercise training between LMA and SEN does not benefit muscle aerobic function or mitochondrial oxidative capacity. Supported by CIHR (AB, RT), CIHR Provincial Training Program in Bone and Joint Health (AB), AHFMR (RT) and NSERC (MT).
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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) | 0.001 | 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 | 0.001 |
| 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".