Effects Of Carrying A Weighted Backpack On Lung Mechanics In Healthy Men
Bibliographic record
Abstract
The use of a weighted backpack is common in occupational and recreational settings. However, it is not known if weighted backpacks alter breathing mechanics or increase the work of breathing (WOB). PURPOSE: To determine the effect of a weighted backpack on breathing mechanics during treadmill walking. METHODS: Subjects (n=7, age=28±6 yrs, ht =180±6 cm) completed five randomized exercise bouts on a treadmill: no backpack (NP), an un-weighted backpack (NW) or a backpack weighing 15, 25 or 35 kg. The backpack trials consisted of two 2.5 min stages, while the NP trial had five 2.5 min stages; to ensure there was an overlap in ventilations. An esophageal balloon catheter was used to estimate pleural pressure and calculate the work of breathing. A maximal expiratory flow volume curve was generated for each condition before and after exercise, while inspiratory capacity manoeuvres were performed during each stage to determine end-expiratory lung volume (EELV). RESULTS: Forced vital capacity (FVC) for the 25 and 35 kg pack trials was decreased compared to all other conditions (P<0.01); however, there was no difference between the NP and NW condition and the 15 kg and NW condition (P>0.05). There was no difference in expiratory flows at: peak, 75% FVC, 50% FVC and 25% FVC between all conditions (P>0.05). Two subjects displayed expiratory flow limitation (7-8% of tidal breath) during the final workload of the 35 kg trial. At the same treadmill grade and speed the 25 and 35 kg conditions had significantly different: minute ventilation, breathing frequency, EELV and WOB; when compared to the 15kg, NW and NP condition (P<0.05). There was no difference in the WOB when comparing different backpack weights at similar minute ventilations (P>0.05). At a similar minute ventilation, independent of trial speed and grade, values were different for the 35 kg backpack and NP condition for breathing frequency (27±4 vs. 22±4 bpm; P<0.01), EELV(25±3 vs. 32± 3 % FVC; P<0.01) and tidal volume (2.0±0.3 vs. 2.5±0.5 l; P<0.01), but were similar for WOB (481±200 vs. 407±116 J·min-1; P>0.05). CONCLUSION: Wearing a weighted backpack alters lung mechanics and the breathing strategy employed during mild to moderate exercise in a normoxic environment; without changing the specific WOB. Funding: The Natural Science and Engineering Research Council of Canada
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".