@article{lawrence_buckner_mirka_2006, title={An adaptive system identification model of the biomechanical response of the human trunk during sudden loading}, volume={128}, ISSN={["0148-0731"]}, DOI={10.1115/1.2165696}, abstractNote={Sudden loading injuries to the low back are a concern. Current models are limited in their ability to quantify the time-varying nature of the sudden loading event. The method of approach used six males who were subjected to sudden loads. Response data (EMG and kinematics) were input into a system identification model to yield time-varying torso stiffness estimates. The results show estimates of system stiffness in good agreement with values in the literature. The average root mean square error of the model’s predictions of sagittal motion was equal to 0.1deg. In conclusion, system identification can be implemented with minimal error and used to gain more insight into the time-dependent trunk response to sudden loads.}, number={2}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Lawrence, BM and Buckner, GD and Mirka, GA}, year={2006}, month={Apr}, pages={235–241} }
 @article{lawrence_mirka_buckner_2005, title={Adaptive system identification applied to the biomechanical response of the human trunk during sudden loading}, volume={38}, ISSN={["1873-2380"]}, DOI={10.1016/j.jbiomech.2004.09.038}, abstractNote={Epidemiological evidence indicates that sudden loading of the torso is a risk factor for low back injury. Accurately quantifying the time-varying loading of the spine during sudden loading events and how these loading profiles are affected by workplace factors such as fatigue, expectation, and training can potentially lead to intervention strategies that can reduce these risks. Electromyographic and trunk motion data were collected from six male participants who performed a series of sudden loading trials with varying levels of expectation (no preview, 300-ms audible preview), fatigue (no fatiguing exertion preceding sudden load, short duration/high intensity fatiguing exertion preceding sudden load), and training (untrained, trained). These data were used as inputs to an adaptive system identification model wherein time-varying lower back stiffness, torque, work, and impulse magnitudes were calculated. Results indicated that expectation significantly increased peak and average stiffness by 70% and 113%, respectively, and significantly decreased peak torque, work, and impulse magnitudes by 36%, 50%, and 45%, respectively. Training significantly decreased peak torque and work by 25% and 34%, respectively. The results also showed a significant interaction between expectation and training wherein training had a positive effect during the trials with preview but no effect during the trials with no preview (increased peak stiffness by 17% and decreased impulse magnitude by 43%).}, number={12}, journal={JOURNAL OF BIOMECHANICS}, author={Lawrence, BM and Mirka, GA and Buckner, GD}, year={2005}, month={Dec}, pages={2472–2479} }
 @article{kelaher_nay_lawrence_lamar_sommerich_2001, title={An investigation of the effects of touchpad location within a notebook computer}, volume={32}, ISSN={["1872-9126"]}, DOI={10.1016/S0003-6870(00)00020-X}, abstractNote={This study evaluated effects of the location of a notebook computer's integrated touchpad, complimenting previous work in the area of desktop mouse location effects. Most often integrated touchpads are located in the computer's wrist rest, and centered on the keyboard. This study characterized effects of this bottom center location and four alternatives (top center, top right, right side, and bottom right) upon upper extremity posture, discomfort, preference, and performance. Touchpad location was found to significantly impact each of those measures. The top center location was particularly poor, in that it elicited more ulnar deviation, more shoulder flexion, more discomfort, and perceptions of performance impedance. In general, the bottom center, bottom right, and right side locations fared better, though subjects' wrists were more extended in the bottom locations. Suggestions for notebook computer design are provided.}, number={1}, journal={APPLIED ERGONOMICS}, author={Kelaher, D and Nay, T and Lawrence, B and Lamar, S and Sommerich, CM}, year={2001}, month={Feb}, pages={101–110} }
 @article{mirka_kelaher_nay_lawrence_2000, title={Continuous assessment of back stress (CABS): A new method to quantify low-back stress in jobs with variable biomechanical demands}, volume={42}, ISSN={["0018-7208"]}, DOI={10.1518/001872000779656525}, abstractNote={ Jobs with a high degree of variability in manual materials handling requirements expose limitations in current low-back injury risk assessment tools and emphasize the need for a probabilistic representation of the biomechanical stress in order to quantify both acute and cumulative trauma risk. We developed a hybrid assessment methodology that employs established assessment tools and then represents their evaluations in a way that emphasizes the distributions of biomechanical stress. Construction work activities in the home building industry were evaluated because of the high degree of variability in the manual material handling requirements. Each task was evaluated using the Revised NIOSH Lifting Equation, The University of Michigan Three- Dimensional Static Strength Prediction Program™, and the Ohio State University Lumbar Motion Monitor Model. The output from each model was presented as time-weighted histograms of low-back stress, and the assessments were compared. The results showed considerable differences in what were considered high-risk activities, indicating that these 3 assessment tools consider the risk of low-back injury from different perspectives. The time-weighted distribution aspect of this methodology also contributed vital information toward the identification of high-risk activities. These results illustrate the necessity for more advanced low-back injury risk assessment techniques for jobs with highly variable manual materials handling requirements. }, number={2}, journal={HUMAN FACTORS}, author={Mirka, GA and Kelaher, DP and Nay, DT and Lawrence, BM}, year={2000}, pages={209–225} }