A Critical Occluding Tension Phase Transition Occurs Between 30% and 40% <scp>1RM</scp> in Dynamic Knee Extension Exercise
Bibliographic record
Abstract
ABSTRACT Oxygen delivery and utilization to working muscle(s) are essential for sustained exercise performance. Higher contractile loads can occlude intramuscular blood vessels, limiting oxygen perfusion, while lighter loads minimize occlusion and allow perfusion. This study explored how external load impacted relative muscle endurance, work capacity, and muscle oxygenation in free‐flow and cuff‐occluded states to estimate the load at which a muscle occludes itself. Twenty‐nine participants (10 untrained (UT), 9 endurance‐trained (ET), 10 resistance‐trained (RT); 14 females, 15 males) completed repetitions to task failure at 15%, 20%, 25%, 30%, 40%, and 80% of their unilateral knee‐extension 1RM in free‐flow and cuff‐occluded states, with muscle oxygenation (SmO 2 ) measured using near‐infrared spectroscopy (NIRS). Compared to cuff‐occlusion, greater work capacity and SmO 2 were observed in the free‐flow state at 15%–30% 1RM ( p < 0.05), but no differences were seen at 40% and 80% 1RM ( p ≥ 0.05). In the free‐flow state above 40% 1RM, RT participants performed more work than UT and ET ( p < 0.05), with no differences between UT and ET ( p ≥ 0.05). At 25% and 30% 1RM, ET and RT participants performed more work than UT ( p < 0.05), with no differences between ET and RT ( p ≥ 0.05). At 15% and 20% 1RM, ET participants performed more work than UT and RT ( p < 0.05). These results suggest a load range of > 30% but ≤ 40% 1RM may represent a phase transition in critical occluding tension of the quadriceps, with contractile induced occlusion occurring above this range, and perfusion occurring below.
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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) | 0.002 | 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".