Documents Garg, Arun 5 results

"The biomechanics of the lower back was reviewed as a basis for establishing a load handling limit. Topics included occupational biomechanics of load lifting, biomechanical basis for back injury, compressive strength of lumbar spinal column, biomechanical models, effect of dynamic factors on spinal stress, intraabdominal pressure, asymmetric lifting, effect of task variables on stresses to spine, vertical location of load, horizontal location of load, speed of lifting, lifting straight up, and lifting technique. Studies have indicated that lifting compact objects of moderate weights close to the body can create compressive forces sufficient to cause damage to some lumbar intervertebral discs. The compressive force is directly related to the horizontal moment arm of the load and thus even light loads should be lifted close to the body through proper workplace design and education and training of the workers. Both the intradiscal pressure and compressive force increase with an increase in angle of trunk flexion. Asymmetric lifting results in significantly lower maximum voluntary muscle strength and higher compressive force, intradiscal pressure, myoelectric activity and antagonistic activity of trunk muscles."

"The review discussed various aspects of guidelines for safe manual lifting. Specific topics covered in the report included low back pain, impairment, disability and compensation; causes of low back pain; comparative analysis of risk factors, age, gender, anthropometry, physical fitness and training, lumbar mobility, strength, medical history, years of employment, smoking, psychosocial factors, and structural abnormalities; job risk factors such as heavy physical work, lifting, bending, stretching and reaching, twisting, pushing and pulling, prolonged standing, vibration, and accidents; and preventive approaches such as radiological screening, lifting techniques, preemployment screening, and ergonomic job design. Studies have indicated that low back pain is an extremely significant cause of disability and has a major socioeconomic impact. Many different personal and job factors are associated with the incidence and prevalence of low back complaints. It is concluded that prospective studies are needed so that factors contributing to the development of low back pain can be separated from factors resulting from low back pain."

"The relationships between work organisational, biomechanical and psychosocial factors were studied using cross-sectional data from a pooled dataset of 1834 participants. The work organisational factors included: job rotation, overtime work, having second jobs and work pace. Task and job level biomechanical variables were obtained through sub-task data collected in the field or analysed in the laboratory. Psychosocial variables were collected based on responses to 10 questions. The results showed that job rotations had significant effects on all biomechanical and most psychosocial measures. Those with job rotations generally had higher job biomechanical stressors, and lower job satisfaction. Overtime work was associated with higher job biomechanical stressors, and possibly self-reported physical exhaustion. Those having second jobs reported getting along with co-workers well. Work pace had significant influences on all biomechanical stressors, but its impact on job biomechanical stressors and psychosocial effects are complicated.
PRACTITIONER SUMMARY:
The findings are based on a large number of subjects collected by three research teams in diverse US workplaces. Job rotation practices used in many workplaces may not be effective in reducing job biomechanical stressors for work-related musculoskeletal disorders. Overtime work is also associated with higher biomechanical stressors."