Number of co-authors:14
Number of publications with 3 favourite co-authors:William S. Marras:4Sue A. Ferguson:3Kimberly A. Vandlen:1
W. Gary Allread's 3 most productive colleagues in number of publications:William S. Marras:34Steven A. Lavender:17Sue A. Ferguson:8
User error: replace user and press any key to continue.
-- Popular computer one-liner
Read the fascinating history of Wearable Computing, told by its father, Steve Mann
Read Steve's chapter !
W. Gary Allread
Publications by W. Gary Allread (bibliography)
Ferguson, Sue A., Allread, W. Gary, Le, Peter, Rose, Joseph D. and Marras, William S. (2011): Shoulder Muscle Oxygenation during Repetitive Tasks. In: Proceedings of the Human Factors and Ergonomics Society 55th Annual Meeting 2011. pp. 1039-1041.
The purpose of this study was to quantify shoulder muscle oxygenation during repetitive shoulder exertions that were similar to motions found in automobile assembly tasks. Ten subjects participated in the study. There were three independent variables: 1) shoulder flexion angle; 2) frequency; and 3) force. The dependent measure was percentage change in muscle oxygenation for the anterior deltoid and trapezius. The results showed significant muscle oxygenation decreases for each of the main effects (shoulder flexion angle, frequency and force). The interaction of force and repetition was significant for the anterior deltoid, indicating that, as repetition increased the magnitude of the differences between the force levels increased. The interaction of repetition and shoulder angle was also significant. The results of this research illustrate that ergonomists need to consider the interaction of injury risk factors that may trigger musculoskeletal disorders of the shoulder.
© All rights reserved Ferguson et al. and/or HFES
Ferguson, Sue A., Marras, William S., Allread, W. Gary, Knapik, Gregory G., Vandlen, Kimberly A., Splittstoesser, Riley and Yang, Gang (2009): Musculoskeletal Disorder Risk Associated with Auto Rotation Angle during an Assembly Task. In: Proceedings of the Human Factors and Ergonomics Society 53rd Annual Meeting 2009. pp. 874-878.
The purpose of this study was to quantify how musculoskeletal disorder exposure risk changes in an auto assembly task as a function of car body rotation. Twelve subjects participated in the study. There were three car body angles including 1) zero or standard, 2) forty-five degrees and 3) ninety degrees from horizontal. Musculoskeletal exposure included spine loads, spine posture, shoulder posture, neck posture and wrist posture, as well as normalized electromyography of the shoulder and neck. The results showed that musculoskeletal disorder exposure risk decreased as the car was rotated to forty-five degrees and further decreased as the car was rotated to ninety degrees. Thus, rotating the car body reduces musculoskeletal exposure which in turn may reduce the risk of musculoskeletal disorders. It should be noted that the results may vary with other assembly tasks.
© All rights reserved Ferguson et al. and/or their publisher
Allread, W. Gary (1993): Dynamics of Trunk Performance during One-Handed Lifting. In: Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting 1993. pp. 659-663.
This study investigated the biomechanical effects of using one hand to perform a materials handling tasks. Subjects were asked to lift a box from a lower to an upper platform using either one or two hands. Three weight levels and four lower platform positions were examined. Subjects wore a back monitor (from which was calculated motion components in the three cardinal planes of the body), stood on a force plate, and were asked to give a rating of perceived exertion for each lift. Results of this study showed that one-handed lifts produced significantly higher ranges of lumbar spine motion in the lateral and transverse planes and greater flexion in the sagittal plane. Back motion risk factors previously found to be associated with high risk of injury jobs all were significantly higher for one-handed lifts. Two-handed lifts, however, produced overall faster motions in the sagittal plane, and equal or larger acceleration and deceleration magnitudes in all planes of motion. Results from the psychophysical measure found no differences in perceived exertion between one- and two-handed lifts. These results suggest that one-handed lifts load the spine more than two-handed lifts due to the added coupling and increase one's risk of suffering a low back disorder. This study also agrees with previous research finding that increased load weight and lifting from asymmetric positions increase risk of low back injury.
© All rights reserved Allread and/or Human Factors Society
Lehman, Katherine R., Allread, W. Gary, Wright, P. Lawrence and Marras, William S. (1993): Quantification of Hand Grip Force under Dynamic Conditions. In: Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting 1993. pp. 715-719.
A laboratory experiment was conducted to determine whether grip force capabilities are lower when the wrist is moved than in a static position. The purpose was to determine the wrist velocity levels and wrist postures that had the most significant effect on grip force. Maximum grip forces of five male and five female subjects were determined under both static and dynamic conditions. The dominant wrist of each subject was secured to a CYBEX II dynamometer and grip force was collected during isokinetic wrist deviations for four directions of motion (flexion to extension, extension to flexion, radial to lunar, and ulnar to radial). Six different velocity levels were analyzed and grip forces were recorded at specific wrist positions throughout each range of movement. For flexion-extension motions, wrist positions from 45 degrees flexion to 45 degrees extension were analyzed whereas positions from 20 degrees radial deviation to 20 degrees ulnar deviation were studied for radial-ulnar activity. Isometric exertions were also performed at each desired wrist position. Results showed that, for all directions of motion, grip forces for all isokinetic conditions were significantly lower than for the isometric exertions. Lower grip forces were exhibited at extreme wrist flexion and extreme radial and ulnar positions for both static and dynamic conditions. The direction of motion was also found to affect grip strength; extension to flexion exertions produced larger grip forces than flexion to extension exertions and radial to ulnar motion showed larger grip forces than ulnar to radial deviation. Although, males produced larger grip forces than females in all exertions, significant interactions between gender and velocity were noted.
© All rights reserved Lehman et al. and/or Human Factors Society
Marras, William S., Lavender, Steven A., Leurgans, Sue E., Rajulu, Sudhakar L., Allread, W. Gary, Fathallah, Fadi A. and Ferguson, Sue A. (1992): Industrial Quantification of Occupationally-Related Low Back Disorder Risk Factors. In: Proceedings of the Human Factors Society 36th Annual Meeting 1992. pp. 757-760.
Few assessment techniques have attempted to define the role of occupational trunk motion in the risk of occupationally-related low back disorder (LBD) even though laboratory studles have indicated that motion significantly increases spine loading. An in-vivo study was performed to assess the contribution of three-dimensional dynamic trunk motions to the risk of LBD during occupational lifting in industry. Over 400 industrial lifting jobs were studied in 48 industries. Specific manual materials handling jobs historically identify as either high risk or low risk for LBD were identified. A tri-axial electrogoniometer was worn by workers and documented the three-dimensional trunk motion characteristics associated with these high risk or low risk jobs. Workplace characteristics such as load moment arm, load weight, etc. were also documented for each of the repetitive lifting tasks. A multiple logistic regression model indicated that a combination of five trunk motion and workplace factors (lifting frequency, load moment, trunk lateral velocity, trunk twisting velocity, and trunk sagittal angle) predicted occupational-related LBD risk well. The analyses have enabled us to determine the LBD risk associated with combined changes in the magnitudes of the five factors. This model could be used as a quantitative, objective measure to redesign the workplace so that the risk of occupationally-related LBD is minimized.
© All rights reserved Marras et al. and/or Human Factors Society
Show this list on your homepage
Join the technology elite and advance:
Changes to this page (author)04 Apr 2012: Added03 Nov 2010: Added
14 Feb 2010: Modified
26 Jun 2007: Added
26 Jun 2007: Added
26 Jun 2007: Added
Page maintainer: The Editorial Team