Splenic constriction during isometric handgrip exercise in humans
Bibliographic record
Abstract
During the first minute of a moderate-intensity isometric handgrip (HG) exercise, there is an increase in stroke volume and cardiac output that occurs without any change in systemic vascular conductance. Although the mechanism of increased venous return is not yet known, current focus has been placed on the constriction of visceral organs. The human spleen represents a compliant organ with high perfusion that constricts during the rather severe stresses of maximal exercise, a diving reflex, or prolonged apnea. This study tested the hypothesis that spleen constriction occurs during isometric HG exercise. Eight participants performed a 1 min isometric HG test at 40% maximum voluntary contraction. Splenic length and width were measured (with ultrasound imaging) after 1 min of exercise, and volume was calculated. To investigate the reflex specificity of this response, spleen dimensions were also measured during 4 min of lower-body negative pressure (LBNP; -20 mm Hg). To test the additional impact of altered breathing and intra-abdominal pressures during the HG, measures were also taken during Valsalva's manoeuvre (VM) at 30 mm Hg. Compared with baseline, both length and width of the spleen were reduced by 0.20 to 0.55 cm (or 4.44%-6.09%; p < 0.05) during each test. This resulted in relative reductions in splenic volume of 13 +/- 1% (HG), 9% +/- 7% (LBNP) and 18% +/- 7% (VM) (p < 0.05; all mean +/- SD). It was concluded that the spleen can constrict during the first minute of isometric HG exercise.
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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 | 0.001 |
| 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".