Strategies Used By Professional Movers To Reduce The Impact Of Carrying Loads And Ways To Assist Them
Bibliographic record
Abstract
Professional movers often carry loads against their backs rather than against their abdomen. When asked about this strategy, they believed it is easier on their backs. However, there is little research on hand-held load carriage. PURPOSE: The purpose of this study was two-fold: (1) to assess the biomechanical differences between hand-held anterior load carriage (ALC) and posterior load carriage (PLC); and, (2) to determine if an assistive load carriage device (ALCD) could reduce muscle effort while carrying loads either anterior or posterior to the pelvis. METHODS: The ALC and PLC were compared using an electromyographic (EMG) analysis while participants carried a load on a treadmill. Isometric maximum voluntary exertions (iMVE) were measured for right side of erector spinae (T9 and L3), trapezius, and anterior and posterior deltoid, rectus abdominalis, external oblique and forearm flexors. Ten male subjects then conducted three trials of 10 strides for the ALC and PLC techniques while carrying 20% body weight in a specialized box. In a second study with an additional 10 male subjects, four conditions were used: ALC, PLC, anterior ALCD and posterior ALCD. Amplitude probability distribution functions (APDF) were used to compare EMG amplitudes at the 10th, 50th, and 90th percentiles. RESULTS: Results indicated that PLC significantly reduced EMG activity of the erector spinae (>50%), trapezius, and anterior deltoid (p<0.05) as well as increasing EMG activity in the posterior deltoid (p<0.05). Results of the second study confirmed that PC significantly reduced erector spinae activity (p<0.05) and moved the shoulder load from the trapezius and anterior deltoid and focused it on the posterior deltoid. The assistive device reduced flexor digitorum activity (>40% reduction, p<0.03) and anterior deltoid activity (>75% reduction, p=0.5) in both ALC and PLC. CONCLUSIONS: There were large reductions (>50%) in erector spinae muscle activity during PLC which explains why professional movers found it easier. When an assistive device was used, back muscle and forearm flexors (>40%) were the main beneficiaries. These results provide evidence that the ALCD used in this study can be an effective ergonomic tool to alleviate grip effort and shoulder activity in both ALC and PLC conditions. Supported by Ontario WSIB Grant #05-07.
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 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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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".