Recovery From Fatigue Of Velocity-dependent Power In Young And Old Men
Bibliographic record
Abstract
Recovery of the neuromuscular system following a bout of fatiguing exercise is important for ongoing mobility function of older adults, but has been seldom measured in previous studies. Furthermore, more attention to velocity-dependent muscle contractions that reflect the capacity to generate muscle power is also needed. PURPOSE: Thus, the effects of fatiguing velocity-dependent shortening contractions on the recovery of knee extensor function in 10 young (∼24 years) and 10 old (∼75 years) men were compared. METHODS: Recovery of neuromuscular properties was assessed immediately and at 0.5, 2, 5, and 10 min following a bout of 30 velocity-dependent (as fast as possible at 20% maximal voluntary isometric contraction (MVC)) shortening contractions. Electrically evoked and voluntary contractions including: maximal twitches, MVCs, and velocity-dependent contractions were compared with baseline and post-task termination measures. RESULTS: For both age groups, at task termination, the MVC was reduced to ∼70% of baseline and did not recover in 10 min. Peak twitch torque, which was reduced to ∼85% of baseline following task termination, recovered in both groups by 5 min. Contraction duration (time to peak twitch + half relaxation time) of the twitch was lengthened to ∼120% in the old men and recovered by 10 min, but contraction duration was not different at any time point for the young. Although velocity-dependent power was reduced more in the old group (to ∼63%) than the young (to ∼80%), recovery was slower in the old men with power not returning to baseline until 5 min, compared with 0.5 min in the young. Recovery of RPE was similar in both age groups from ∼8 at task termination to ∼4 by 10 min. CONCLUSIONS: There is no relative age-related difference in the recovery of isometric strength in response to velocity-dependent fatigue. Conversely, power was reduced to a greater extent in the old men than the young and recovery was blunted for the old. These results indicate how recovery from a fatigued muscle state depends not just upon the task, but also on the contractile property that is measured. Supported by NSERC and NLCAHR
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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 | 0.001 |
| 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".