­
­
­
­

Inventi Impact - Biomedical Engineering

Articles

  • Inventi:ebe/8839/14
    PEAK HIP AND KNEE JOINT MOMENTS DURING A SIT-TO-STAND MOVEMENT ARE INVARIANT TO THE CHANGE OF SEAT HEIGHT WITHIN THE RANGE OF LOW TO NORMAL SEAT HEIGHT
    Shinsuke Yoshioka, Akinori Nagano, Dean C Hay, Senshi Fukashiro

    Background: Previous studies have consistently reported that decreasing seat height increases the peak hip and knee joint moments; however, these findings may not apply to biomechanical changes at very low seat heights. The purpose of this study, therefore, was to examine the effect of a large range of seat heights on peak joint moments of the lower limb during a sit-to-stand (STS) movement. Methods: Eight healthy young subjects participated in this experiment. Each subject was instructed to stand up from six seat heights (10, 20, 30, 40, 50 and 60 cm). Joint moments were calculated with an inverse dynamics method. The sum of the hip and knee joint moments was used as the index to indicate the mechanical load of the STS movement. The effect of seat height on the mechanical load was examined with both analytical and experimental approaches. Results: Through the analytical approach, it was revealed that the mechanical load of STS movements from low and normal seat heights (10 to 40 cm) always reaches its peak at or near the posture in which the thigh is horizontally positioned. This finding indicates that the peak value is invariant between the low and normal seat heights. Similar results were also found in the experimental approach. There were few significant differences in the peak mechanical load and the peak hip and knee joint moments between the low and normal seat heights, while they differed significantly between the low and high seat heights. Conclusions: This study concluded that, while the peak mechanical load and the peak hip and knee joint moments increase inversely to seat height within the range of high to normal seat height (60 to 40 cm), they are invariant to the change of seat height within the range of low to normal seat height (10 to 40 cm). These findings are useful for the design of chair, the improvement in the evaluation standard of minimum sit-tostand height tests and the development of new muscular strength test.

    How to Cite this Article
    CC Compliant Citation: Yoshioka et al.: Peak hip and knee joint moments during a sit-tostand movement are invariant to the change of seat height within the range of low to normal seat height. BioMedical Engineering OnLine 2014 13:27, doi:10.1186/1475-925X-13-27. © 2014 Yoshioka et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
    Download Full Text