IS CHILDREN’S FASTER RECOVERY FROM EXERCISE DUE TO A HIGHER METABOLITE CLEARANCE RATE?
Bibliographic record
Abstract
Dear Editor-in-Chief: We are writing regarding a recent article by Zafeiridis et al. (5), comparing recovery from high-intensity exercise in boys, adolescents, and adults. A faster recovery of performance capacity (knee flexion/extension) was demonstrated in children and adolescents compared with adults. It was concluded that recovery rate was maturity dependent. While the study and its results are well presented, we believe there is a significant discussion oversight regarding the mechanisms underlying this phenomenon. The authors speculate that a possible explanation may be a higher metabolite (lactate, H+) clearance rate in children: “Based on these facts, the possibility that the boys and teens in the current study had faster removal of lactate that facilitated the recovery process should not be excluded” (p. 511). The authors failed to consider the experimental evidence that contradicts their explanation. We addressed this very issue in a paper by Dotan et al. (1), which demonstrated, that blood lactate (La) disappearance rate following high-intensity exercise, is strikingly similar in children and adults, despite markedly different peak values ([La]peak). It was shown that not only was children’s La-disappearance half-time similar to that of adults, but that there was no difference between their La-recovery curves following similar [La]peak values. The only consistent difference being children’s shorter lag time to [La]peak. Therefore, it was argued that faster recovery in children is not due to a more efficient metabolite clearance rate, but rather to the fact that they have less to recover from (lower power output and La production) and that their [La]peak is reached sooner. The evidence of children’s lower sympathetic activation (3) that Zafeiridis et al. (5) cite in support of their view only supports our notion that children are anaerobically inferior, precisely because they are unable to fully mobilize their sympathetic system and recruit higher hierarchy motor units. This would explain their lower La production but not a faster La clearance. This is not to exclude other factors that separate boys from men (e.g., faster phosphocreatine resynthesis (2,4)). However, future research may well demonstrate that many or all of these differences stem from the alleged maturation-related difference in recruitment potential. Bareket Falk Raffy Dotan Brock University, Department of Physical Education and Kinesiology, St. Catharines, Ontario, 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 | 0.003 | 0.031 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.006 | 0.006 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".