William L Porter
Affiliation: Centers for Disease Control and Prevention
- Forces and moments on the knee during kneeling and squattingJonisha P Pollard
National Institute for Occupational Safety and Health, Office of Mine Safety and Health Research, Pittsburgh, PA, USA
J Appl Biomech 27:233-41. 2011..One Knee resulted in the highest force magnitudes and net moments (p < .001) of the kneeling postures. Thigh-calf and heel-gluteus contact forces decreased the flexion moment on average by 48% during Squat and Near Full...
- Analysis of applied forces and electromyography of back and shoulders muscles when performing a simulated hand scaling taskWilliam Porter
Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA
Appl Ergon 41:411-6. 2010..Results of these studies suggest that miners scale points on the rock face that are below their knees, and reposition the bucket as often as necessary to do so...
- Pressure distribution on the anatomic landmarks of the knee and the effect of kneepadsWilliam L Porter
Office of Mine Safety and Health Research, National Institute for Occupational Safety and Health, 626 Cochrans Mill Road, PO Box 18070, Pittsburgh, PA 15236, United States
Appl Ergon 42:106-13. 2010..The major conclusion of this study is that novel kneepad designs that redistribute the stresses at the knee across a greater surface area and to other regions of the leg away from key structures of the knee are needed...
- Locomotion in restricted space: kinematic and electromyographic analysis of stoopwalking and crawlingSean Gallagher
National Institute for Occupational Safety and Health, Office of Mine Safety and Health Research, Pittsburgh, PA 15236 0070, USA
Gait Posture 33:71-6. 2011..05); however, subjects complained of discomfort without kneepads (especially in two-point crawling). Results of this study have implications for work performed in underground coal mines, as well as emergency or evacuation considerations...
- Electromyography of the thigh muscles during lifting tasks in kneeling and squatting posturesSean Gallagher
National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, Pittsburgh, PA, USA
Ergonomics 54:91-102. 2011..This paper examines the EMG responses of knee extensors/flexors to lifting in these postures, discusses the impact of posture and kneepads on muscle recruitment and explores the implications for work in such postures...