| Objective: To consider the design features of backpacks in light of current scientific knowledge. Particular focus is drawn to the methods used to assess the benefits of assisted load carrying. The second objective is to discuss the increasingly dated knowledge regarding clinical use of surface EMG (s-EMG) and Ratings of Perceived Exertion (RPE) as valid tools in the assessment. Data Sources: The current scientific literature was examined using the MEDLINE® database and was accessed using the PUBMED® online search engine. The MANTIS® database was also searched for additional material. Study Selection: Forty-six journal articles were chosen from a selection of 104 that had satisfied the online search criteria and pertained to the aims of this discussion. Data Extraction: Journal articles were included based on relevance to the topics discussed. Selected articles had particular results pertaining to either electromyography (EMG), RPE assessment of different load carriage methods, load placements on the spine and the effects loads have on the spine and gait. Data Synthesis: From the literature, we find that s-EMG is a valid tool for use in clinical assessment of muscular effects of load on the human frame. We have found that more extensive trials need to be performed, using larger sample sizes, matched groups and extensive sampling points in order that s-EMG can be readily utilised by the wider scientific community for such analyses. Conclusion: It is apparent that placement of a load as close as possible to the centre of mass of the body is important, especially when considering these concepts to relate the weight carried to fatigue, as well as to specific bag design features. There is evidence to suggest that in the adult population fatigue can be reduced if loads are kept as close as possible to 30% of the wearer’s lean body mass, while the 10% maximum load for children is a figure that requires further exploration in order to justify completely. The literature supports use of a combination of both s-EMG and Borg scales (RPEs) as acceptable, valid, repeatable measures to test the body’s responses to loads using different backpack designs. This abstract is reproduced with the permission of the publisher; full text (print only) by subscription.
|
