Occupational Ergonomics - Volume 2, issue 1

Authors: Villalta, Dino L. | Stevenson, Joan M. | Pearce, G. William | Brereton, Lisa C.

Article Type: Research Article

Abstract: The purpose of this study was to develop and validate a one camera analysis strategy to correct for the effects of perspective error due to out of plane rotation on the calculation of L4/L5 moment and compression and shear forces. A mathematical model was derived around the geometric relationship of a T-Bar shaped device and the measured camera to object plane distance. This geometric relationship was used to reorient a rotated subject back into the perpendicular film plane before calculation of joint moments and forces. Systematic errors (rotational perspective errors, forward/backward and side/side distances of subject from camera) and random …errors (digitization error, anthropometrics, lifting techniques) were determined with maximum errors of 10.5%, within ±20 degree out of plane rotations. Results generally supported incorporation of a correctional device to extend the use of two-dimensional analysis strategies in industrial settings. Show more

Keywords: perspective error, photogrammetry, computer modelling, lumbar moments, spine, lifting

DOI: 10.3233/OER-2000-2101

Citation: Occupational Ergonomics, vol. 2, no. 1, pp. 3-15, 2000

Authors: Straker, Leon | Cain, Carol

Article Type: Research Article

Abstract: A comparison between semi-squat and squat techniques was made for floor to knuckle height lifting using maximum acceptable weight (MAW), ratings of perceived exertion (RPE) and heart rate. Semi-squat lifting resulted in greater MAW with lower RPE and lower heart rate compared to squat lifting. Discomfort was most commonly reported in knees/quadriceps with squat lifting. Twelve of the 13 subjects preferred the semi-squat technique. The results provide evidence that the semi-squat technique may have benefits over the squat technique for lifting a medium sized box from floor to knuckle height.

Keywords: lifting technique, maximum acceptable weight, exertion, heart rate

DOI: 10.3233/OER-2000-2102

Citation: Occupational Ergonomics, vol. 2, no. 1, pp. 17-26, 2000

Authors: Baker, Nancy A. | Jacobs, Karen | Carifio, James

Article Type: Research Article

Abstract: This study identified which combination of background factors, work practice, and psychosocial variables could discriminate most accurately between individuals with mild, moderate, or severe musculoskeletal discomfort in a population of 155 customer service representatives of a telecommunications company. These risk profiles were obtained for overall upper body musculoskeletal discomfort, as well as for each individual body part (neck, shoulder, elbow, wrist/hand, and back). Results of discriminant analyses suggested that risk profiles were different for each body part and could accurately classify from between 50 and 100% mild, moderate, or severe discomfort categories. These risk profiles were all highly significant (<0.01). …This research identified the amount of social support, job variety, and skill utilization on the job as the psychosocial variables most often associated with musculoskeletal discomfort in this population. Show more

Keywords: WRMD, discriminant analysis, profiles, biomechanics

DOI: 10.3233/OER-2000-2103

Citation: Occupational Ergonomics, vol. 2, no. 1, pp. 27-41, 2000

Authors: Zhang, Zhijun

Article Type: Research Article

Abstract: This study examined the effects of lifting technique, lifting frequency and lifting weight on oxygen uptake, pulmonary ventilation, heart rate, and rating of perceived exertion of the Chinese population. The physiological and psychological responses increased significantly with repetitive lifting workload. The workload was calculated from several lifting task characteristics including lifting frequency, lifting weight and lifting distance. The regressive formulas were produced statistically. The metabolic costs and psychological feeling could be reliably predicted from repetitive lifting workload and lifting technique. The workload limits of specific lifting tasks could be estimated by comparing predicted metabolic costs and psychological feelings with relevant …available physiological and psychological tolerances of Chinese population. The study further revealed that lifting technique significantly affected lifting capacities. Show more

Keywords: metabolic cost, psychological feeling, workload limit, repetitive lifting workload, lifting technique

DOI: 10.3233/OER-2000-2104

Citation: Occupational Ergonomics, vol. 2, no. 1, pp. 43-51, 2000

Authors: Wood, Kathleen K. | Schulze, Lawrence J.H. | Chen, Jen-Gwo | Cleveland, Theodore G.

Article Type: Research Article

Abstract: A study was conducted to determine how the position of the handwheel affected the amount of torque applied by an operator. Data were collected at a series of wheel heights and distances. Results indicate that the main effects of gender, wheel height, and wheel distance, and the interaction between gender and wheel distance were statistically significant. No practical differences in torque production among the 5 wheel heights used in this investigation were found. A strong correlation existed between torque production capability and a handwheel height of 101.6 cm and weight of the male participants.

Keywords: handwheel, torque, dynamometer, valve operation

DOI: 10.3233/OER-2000-2105

Citation: Occupational Ergonomics, vol. 2, no. 1, pp. 53-65, 2000