Anterior Tibial Artery Blood Flow is Unaffected by Age during a Fatiguing Submaximal Dorsiflexor Contraction
Bibliographic record
Abstract
Muscle blood flow is a critical factor in the ability to maintain exercise, particularly during isometric efforts. However, relatively few studies have directly monitored blood flow during isometric exercise. PURPOSE: To use Doppler ultrasound and near-infrared spectroscopy to assess the effect of healthy aging on dorsiflexor blood flow and tissue oxygenation during a sustained isometric contraction. METHODS: Fifteen young men (24 ± 2 years) and 15 old men (76 ± 4 years) performed a contraction at 60% of maximal strength until exhaustion. Mean blood velocity (MBV) was recorded from the anterior tibial artery and diameter measures were obtained off-line to calculate mean blood flow (MBF) through the artery. RESULTS: Old men were 17% weaker and had a longer time-to-exhaustion than young men (107.1 ± 30.9s and 81.9 ± 19.8s, respectively). Arterial diameter, total hemoglobin and oxygenation decreased in both groups but to a greater extent in young. MBV and MBF increased throughout exercise and were not different between groups. After exercise, diameter increased to a greater degree in young than old men. Both groups had a striking increase in MBV and MBF following exercise but the effect was two-fold greater in young than old. The post-contraction increases in total hemoglobin and oxygenation were not different between groups. CONCLUSIONS: These data suggest that despite similar MBF in the anterior tibial artery during exercise, muscle perfusion was impaired to a greater extent in the stronger young men than in the weaker old men, but at a site distal to the conduit artery.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".