Matched work high-intensity interval and continuous running induce similar increases in PGC-1α mRNA, AMPK, p38, and p53 phosphorylation in human skeletal muscle
Bibliographic record
Abstract
The aim of the present study was to test the hypothesis that acute high-intensity interval (HIT) running induces greater activation of signaling pathways associated with mitochondrial biogenesis compared with moderate-intensity continuous (CONT) running matched for work done. In a repeated-measures design, 10 active men performed two running protocols consisting of HIT [6 × 3-min at 90% maximal oxygen consumption (Vo(2max)) interspersed with 3-min recovery periods at 50% Vo(2max) with a 7-min warm-up and cool-down period at 70% Vo(2max)] or CONT (50-min continuous running at 70% Vo(2max)). Both protocols were matched, therefore, for average intensity, duration, and distance run. Muscle biopsies (vastus lateralis) were obtained preexercise, postexercise, and 3 h postexercise. Muscle glycogen decreased (P < 0.05) similarly in HIT and CONT (116 ± 11 vs. 111 ± 17 mmol/kg dry wt, respectively). Phosphorylation (P-) of p38MAPK(Thr180/Tyr182) (1.9 ± 0.1- vs. 1.5 ± 0.2-fold) and AMPK(Thr172) (1.5 ± 0.3- vs. 1.5 ± 0.1-fold) increased immediately postexercise (P < 0.05) in HIT and CONT, respectively, and returned to basal levels at 3 h postexercise. P-p53(Ser15) (HIT, 2.7 ± 0.8-fold; CONT, 2.1 ± 0.8-fold), PGC-1α mRNA (HIT, 4.2 ± 1.7-fold; CONT, 4.5 ± 0.9-fold) and HSP72 mRNA (HIT, 4.4 ± 2-fold; CONT, 3.5 ± 1-fold) all increased 3 h postexercise (P < 0.05) although neither parameter increased (P > 0.05) immediately postexercise. There was no difference between trials for any of the above signaling or gene expression responses (P > 0.05). We provide novel data by demonstrating that acute HIT and CONT running (when matched for average intensity, duration, and work done) induces similar activation of molecular signaling pathways associated with regulation of mitochondrial biogenesis. Furthermore, this is the first report of contraction-induced p53 phosphorylation in human skeletal muscle, thus highlighting an additional pathway by which exercise may initiate mitochondrial biogenesis.
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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) | 0.002 | 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".