The effects of lower limb muscular fatigue and work experience on patterns of falling in workers.
Mangharam-J; Bhattacharya-A; Succop-P; Bagchee-A
Proceedings of CybErg 1999: The Second International Cyberspace Conference on Ergonomics. Perth, Australia: The International Ergonomics Association Press, 1999 Jan; :1-10
The aim of this study is to measure the effects of muscular fatigue and work experience on patterns of movement during a forward falling task Eleven subjects, 6 experienced and 5 inexperienced workers of elevated and/or inclined surfaces, participated in the study The subjects were required to voluntarily fall forwards in a sagittal plane (Emax task) The Emax task was carried out before and after a fatiguing task of the lower limb musculature To characterise pattern of movement, horizontal displacement and velocity of the center of gravity (COG) was measured by two-dimensional kinematic analysis Electromyography (EMG) was utilised in synchrony, to describe the associated muscular activity levels of the left and right gastrocnemius, tibialis anterior, quadriceps and hamstrings muscles A general linear model was utilised to carry out repeated measures analysis of covariance Repeatability tests revealed that all independent variables, except for relative EMG levels of tibialis anterior of the initially weight bearing limb, did not vary significantly between trials The results show that during an Emax task, if an individual's base of support is not restricted from being displaced forward by a step, then the COG could be displaced in a horizontal plane beyond the base of support, prior to the first detection of a stepping motion (heel rise). The COG displacement during an Emax task was significantly less after fatigue of the lower limbs (F=5.14, p=0.05; non-fatigued mean =0.1653m, fatigued mean =0.1555m) These results support past studies, which suggest that fatigue of the lower limb musculature increases co-contraction around the joints, reducing sway and step length Experienced workers had higher relative electrical activity of the hamstrings muscle of the stepping limb, especially during terminal swing, compared to inexperienced workers (F=558; p=0.05) These results show that experienced workers have more appropriate muscle activity during a Emax task, as it is usually expected that high hamstring eccentric activity occurs in the stepping limb during terminal swing to decelerate the swinging limb The results from the current study suggest that training workers in high risk fall environments should not be limited to education and personal protective equipment alone, but should also include the implementation of occupational specific physical exercises.
Muscle-physiology; Muscle-function; Musculoskeletal-system; Fatigue-properties; Accident-statistics; Accident-analysis; Work-performance; Work-analysis; Workplace-studies; Kinetics; Accident-prevention; Physiological-fatigue; Physiological-function; Physiological-testing; Body-mechanics
Biomechanics-Ergonomics Research Labs and Epidemiology/Biostatistics Division, Department of Environmental Health, College of Medicine, University of Cincinnati, Cincinnati, OH 45267-0056
Research Tools and Approaches; Risk Assessment Methods
Proceedings of CybErg 1999: The Second International Cyberspace Conference on Ergonomics
University of Cincinnati, College of Medicine, Cincinnati, Ohio