Number of co-authors:15
Number of publications with 3 favourite co-authors:William S. Marras:4Sue A. Ferguson:2Kenneth Johannaber:1
Fadi A. Fathallah's 3 most productive colleagues in number of publications:William S. Marras:34Steven A. Lavender:17Karl H. E. Kroemer:8
...that strange new zone between medium and message. That zone we call the interface
-- Steven Johnson, 1997
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The Social Design of Technical Systems: Building technologies for communities
by Brian Whitworth and Adnan Ahmad
The Encyclopedia of Human-Computer Interaction, 2nd Ed.
by Mads Soegaard and Rikke Friis Dam
Fadi A. Fathallah
Publications by Fadi A. Fathallah (bibliography)
Nou, Danny, Miller, Brandon J. and Fathallah, Fadi A. (2012): Low Back Muscle Fatigue Measurements of Cyclic and Prolonged Stooped Work. In: Proceedings of the Human Factors and Ergonomics Society 2012 Annual Meeting 2012. pp. 1196-1200.
Fatigue experiments were performed on human subjects to study muscle fatigue measurements of the erector spinae muscles during cyclic and prolonged static stooped bending using electromyography (EMG). Nineteen subjects participated in the study. The median muscle firing frequency (fm) data of the erector spinae muscles were measured noninvasively and continuously during simulated cyclic and prolonged stooped work. In the prolonged condition, the subject conducted an isometric stooped work at 4:1 work to rest ratio; whereas in the cyclic condition, the subject conducted an isometric stooped work at 4:1 work-to-rest ratio; each followed by a recovery period. To quantify the rate of fatigue, a fatigue index was defined as the change in the fm with respect to muscle activation time. All measurements were normalized to each subject's individual erector spinae maximum voluntary contraction using the Biering-Sřrenson Muscle Endurance test for lower back endurance as control measurement. The results indicated that the use of EMG showed no significant differences in the muscle fatigue between cyclic and prolonged stooped conditions. However, when EMG results for both are compared to the control conditions, similar fatigue responses are shown. This may be an indication that both cyclic and prolonged stooped work conditions are equally detrimental to the spine, which calls for effective interventions to limit their effects on workers who commonly perform these types of tasks.
© All rights reserved Nou et al. and/or Human Factors and Ergonomics Society
Johannaber, Kenneth and Fathallah, Fadi A. (2011): Disc Hydration Response to Simulated Stooped and Erect Postures. In: Proceedings of the Human Factors and Ergonomics Society 55th Annual Meeting 2011. pp. 1017-1021.
Evidence suggests that prolonged exposure to stooped work is associated with the development of low back disorders, particularly those that affect the spinal intervertebral discs. While several studies have been done to analyze the biomechanical aspects of stooped work, very little research has focused on the effect of prolonged stooped work on disc hydration -- a critical component of disc health. This study explores the connection between stooped work and low back pain through controlled mechanical loading and quantitative analysis of disc hydration during in vitro simulated stooped and erect loading conditions of porcine discs. The results showed that stooped postures exhibit significantly decreased overall water content relative to erect postures. These results have implications for the injury mechanisms associated with stooped work, as disc hydration forms the foundation for overall disc health and proper function.
© All rights reserved Johannaber and Fathallah and/or HFES
Ulrey, Brent L. and Fathallah, Fadi A. (2011): Biomechanical Effects of a Personal Weight Transfer Device in the Stooped Posture. In: Proceedings of the Human Factors and Ergonomics Society 55th Annual Meeting 2011. pp. 1052-1056.
Repetitive work in the stooped posture is a known risk factor for developing low back disorders (LBDs). Use of the stooped posture in the workplace is widespread throughout the world in agriculture, construction, and mining. In California alone, hundreds of thousands of agricultural field workers routinely utilize the stooped posture. The purpose of this study is to evaluate if a personal weight transfer device as a possible intervention to reduce the load on the lumbar spine, thereby reducing the risk of developing LBDs. Eighteen healthy subjects performed stoop posture tasks in a laboratory study designed to simulate harvesting of low-growing crops. Results showed that when wearing the device in the static stooped posture, biceps femoris activity was reduced
© All rights reserved Ulrey and Fathallah and/or HFES
Fathallah, Fadi A. and Marras, William S. (1995): Spinal Coupled Motions and Their Association with the Risk of Low Back Disorders in Industrial Tasks. In: Proceedings of the Human Factors and Ergonomics Society 39th Annual Meeting 1995. p. 959.
Occupational low back disorders (LBDs) have been responsible for a great deal of human suffering while imposing a tremendous financial burden on the affected individuals, their employers, and the health insurance providers. Several epidemiological and in-vitro studies have implicated Combined motions and loads of the back to constitute highly undesirable lifting situations. However, up to this date, there were no studies that quantitatively assessed trunk coupled or combined motions of industrial workers. Therefore, the main purpose of this study was to quantify the simultaneous multi-dimensional coupled motions (velocities) of the trunk in various manual materials handling (MMH) jobs with varying degrees of LBD risk. The results showed that representing information in a continuous multivariate space revealed information that would be otherwise obscured in a univariate dimension. In addition, there seem to be a threshold of sagittal bending where, if surpassed, dynamic coupled motions were most pronounced in high and medium risk groups. The results were in agreement with empirical findings that showed how coupled situations similar to the ones observed in this study may have adverse effects on the spinal structure. Investigating, in details, the role of combined dynamic risk factors help the process of comprehending low back injury mechanism, and abating LBDs in industrial settings.
© All rights reserved Fathallah and Marras and/or Human Factors Society
Fathallah, Fadi A., Wright, Patrick L. and Marras, William S. (1993): Variation in Trunk Mobility throughout the Work Day. In: Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting 1993. pp. 664-668.
Low back disorders have been a major concern for both industries and the public in general. Diurnal variation in trunk flexibility has been previously observed and quantified in terms of range of motion. It was hypothesized that decreased disc height as the day progresses allows the spinal ligaments to slacken, resulting in an increase in the range of motion (flexibility) and possible reduction in risk of injury. Evidence suggests that this risk may be accentuated under dynamic motions of the spine. This experiment focused on observing the change in dynamic components of trunk flexibility (trunk mobility) as a function of time of the day. Trunk motions of twenty-one male participants were obtained at three specific times of the day using a tri-axial electrogoniometer. No variation in trunk range of motion in any of the cardinal planes was observed. However, velocity and acceleration in the sagittal plane showed significant variations, suggesting the re-examination of the "slack ligaments" hypothesis. This study asserts that identifying flexibility by only its static component, range of motion, gives only partial information. Industrial injuries occurring in the early morning hours may be a result of insufficient trunk mobility. The relation between trunk mobility and back injury incidence rates should be further investigated.
© All rights reserved Fathallah et al. and/or Human Factors Society
Ferguson, Sue A., Fathallah, Fadi A., Granata, Kevin P., Kim, Jung Y. and Marras, William S. (1993): Coactivity Effects upon Carpal Tunnel Contact Forces. In: Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting 1993. pp. 705-709.
Contact force on the carpal tunnel structures due to flexor tendon forces have been identified as an important contributor to the compression of the median nerve. Therefore, a pilot study was conducted to assess the increase ln carpal contact force due to the antagonistic coactivity of the finger extensor muscles. Surface EMG activities of the superficial finger flexor and extensor muscles of four subjects were measured during several isometric power grip exertions at seven different wrist angles. The results showed that a linear relation between EMG and muscle force holds under the prescribed isometric conditions. An EMG-assisted model was developed to predict tensile forces in an equivalent flexor tendon. For a given angle, the model predicts increased tensile force in the flexor tendon with increased extensor (antagonist) coactivity in response to isometric grip exertions. It was found that if one accounts for muscle coactivity, predisted force in the flexor tendons would be as much as 33% greater than force predicted by models which neglect coactivity. This increase would also be observed in carpal contact force since this force is linearly related to the flexor tendon force. Models that neglect coactivity severely underestimate flexor tendon forces and consequently contact forces in the carpal tunnel.
© All rights reserved Ferguson 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
Kroemer, Karl H. E., Fathallah, Fadi A. and Langley, Lawrence W. (1988): A New Keyboard with Chorded Ternary Keys. In: Proceedings of the Human Factors Society 32nd Annual Meeting 1988. pp. 724-726.
A new keyboard has been used in preliminary tests. Each key has 3 state conditions ("ternary key") and is moved by horizontal displacement of the fingertip, usually together with another key ("in "chords"). Little is known about the usability of such a Ternary Chord Keyboard (TCK) from previous experiments. Pilot tests indicated fast performance with a TCK.
© All rights reserved Kroemer et al. and/or Human Factors Society
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