Postural effects on biomechanical and psychophysical weight-lifting limits
| Autor: | Don B. Chaffin, G B Page |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Adult
Male Engineering medicine.medical_specialty Posture Population Physical Therapy Sports Therapy and Rehabilitation Human Factors and Ergonomics Squat Biomechanical Phenomena Weight-Bearing Physical medicine and rehabilitation Risk Factors Psychophysics medicine Humans Computer Simulation education Simulation education.field_of_study Lumbar Vertebrae business.industry Lift (data mining) Biomechanics Spinal column Sagittal plane Occupational Diseases medicine.anatomical_structure business Low Back Pain Population variance |
| Zdroj: | Ergonomics. 37:663-676 |
| ISSN: | 1366-5847 0014-0139 |
| DOI: | 10.1080/00140139408963681 |
| Popis: | Many believe that biomechanical models and data are not sufficiently refined and validated to be used as the basis for setting 'safe' population load lifting limits. Rather, they advocate that such limits should be based on what a sample of the population demonstrate to be 'maximum acceptable weight limits' (MAWL) resulting from psychophysical tests performed with different populations. Yet, biomechanical models are becoming more robust and valid. Computerized versions of these models are readily available, and these models now can provide a more complete understanding of the pathophysiology of a person's spinal column and supporting structures, thereby providing a means to predict the risk of tissue trauma in given lifting situations for large size populations. NIOSH has recognized the validity of both biomechanics and psychophysics for establishing a Recommended Weight Limit (RWL) in the United States. The implications of using both types of methods and data are explored in this paper. Three case studies are presented that involve infrequent lifting of varied size boxes from near floor level to explore how MAWL and biomechanically determined limits differ. The cases include symmetric, sagittal plane lifting using a freestyle posture, a similar lift but with freestyle and squat lift postures, and an asymmetric load lifting task. In all three case comparisons it is shown that a recommended load to be lifted based solely on a spinal disc compression force tolerance of 3400 N would be much lower than published MAWL values representing 75% or even 90% of young males under 40 years old (i.e. MAWL values may not be protective of some young males). It also is shown that MAWL values do not have as much population variance as the spinal motion segment failure values. Hence, many younger males would be expected to have spinal columns that can tolerate the highest published MAWL values. Several mitigating factors, including load lifting trajectories, lifting dynamics, and biomechanical modeling limitations are discussed, as well as differences in compressive force tolerances and MAWLs associated with age and gender. |
| Databáze: | OpenAIRE |
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