Sudden load and the lower back effect of load application and lumbar support.
Visual inspection methods and biomechanical modeling was applied to estimate the disc reaction forces and moments when sudden loads perturbed the trunk via both direct loading to the chest and the loading to the hands. Also, the effectiveness of a lumbar support was analyzed using the variables of e...
| Published in: | Sudden Load & the Lower Back Effect of Load Application & Lumbar Support pp. 160 p - 161 |
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| Format: | research Doctoral Dissertation |
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University of Iowa
2001
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=109876501&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 109876501 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: isbn: 9780493472171 dissinfo: disstl: Sudden load and the lower back effect of load application and lumbar support. dissinst: University of Iowa jinfo: jid: IL8H jtl: Sudden Load & the Lower Back Effect of Load Application & Lumbar Support maglogo: N pubinfo: dt: 2001 pub: University of Iowa artinfo: ui: 109876501 109876501 2003103153 UMI Order AAI3034121 109876501 ppf: 160 p ppct: 1 formats: tig: atl: Sudden load and the lower back effect of load application and lumbar support. aug: au: Lee S sug: subj: Weight-Bearing Intervertebral Disk Physiology Muscle, Skeletal Physiology Lumbar Vertebrae Orthoses Comparative Studies Random Assignment Electromyography Kinematics Algorithms Body Height Body Weight Right-Handedness Sex Factors Age Factors Male Adult Human Adult: 19-44 years Male ab: Visual inspection methods and biomechanical modeling was applied to estimate the disc reaction forces and moments when sudden loads perturbed the trunk via both direct loading to the chest and the loading to the hands. Also, the effectiveness of a lumbar support was analyzed using the variables of electromyography signal and biomechanical modeling.The sample for this study consisted of twenty-four right-handed males, who did not have any history of back pain at the time of study. The average age of the subject was 29.9 years and the average height and weight were 1.74 m and 80.4 kg. The tests consisted of two sudden load conditions and subjects were randomly assigned into 4 groups. Four groups of six subjects each were tested in different orders of loading location, lumbar support order, and repetition. Each trial was conducted 4 times.Visual inspection method was used with the criterion obtained from the experience of reviewing more than 4,000 cases of surface electromyography signal of fast moving erector spinae muscles. Using the trajectories of center of gravity and center of pressure of the body and equations of motion allowed the estimation of fast lower-back movement profile. An optimization algorithm, which included the EMG and kinematic data from the linked segment dynamics model, was used to estimate disc reaction forces and moments.Hand loading evoked much faster back muscle firing onset time (RT, reaction time) than chest loading. The reaction time of trunk back muscles occurred in the region of the triggered reaction, which has moderate flexibility and large dependency on instructions received. The discs' inertia and stiffness provide a small, passive resistance to destabilizing perturbations. Maximum compression force occurred when the voluntary movements occurred. For both the chest and hand loading conditions, the lumbar support decreased the maximum predicted shear force and flexion moment. The lumbar support also decreased the muscle response ratio, a ratio of resting and active EMG rms values, both for the chest and hand loading conditions. pubtype: Dissertation doctype: research Doctoral Dissertation ougenre: Unknown language: English refInfo: holdings: @attributes: islocal: N |
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