Oral Contraceptive Use Does Not Influence The Response To Contraction-induced Muscle Damage
Bibliographic record
Abstract
Eccentrically-biased exercise induces skeletal muscle damage and repair through skeletal muscle stem cells referred to as satellite cells (SC). The response to damaging contractions may be affected by endogenous or exogenous synthetic sex steroid hormones, such as those from oral contraceptives (OC); however, the effect of OC use on the response to damaging contractions remains unknown. PURPOSE: We sought to characterize the effect of OC use on skeletal muscle damage and the subsequent SC response to eccentric contraction-induced damage versus women who were not taking OC and were normally cycling (NC). METHODS: Thirty-two healthy young females (21 ± 3 years [mean ± SD]) underwent 300 maximal eccentric leg extensions on an isokinetic dynamometer, and measurements were made prior to and at 0 h, 24 h, 48 h, and 72 h after muscle damage. Skeletal muscle biopsies were collected from the vastus lateralis. Serum samples were collected to determine concentrations of creatine kinase (CK). Strength (maximal voluntary contraction) and soreness (visual analog scale) measurements were also collected. RESULTS: There were no significant differences between NC and OC groups in the SC response, with no changes in SC abundance detected across time (NC: 6.6 ± 3.4 Pax7+ cells/100 fibers, OC: 7.1 ± 2.6 Pax7+ cells/100 fibers; p > 0.05). CK increased (p < 0.05) in both groups up to 72 h post-damage with no differences between groups (NC: 278 ± 172 U/L; OC: 357 ± 221 U/L), and a loss in strength was observed immediately post-damage in both groups and remained until 72 h, also with no differences between groups. CONCLUSION: NC and OC users experienced similar strength loss and demonstrated no difference in CK release or SC mobilization in response to damaging contractions.
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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) | 0.006 | 0.001 |
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".