The goal of this proposed research is to determine which interventions, such as alternative keyboard designs, workstation arrangements, and typing styles lead to reduced static and dynamic loading of the tissues of the upper extremity, hence reducing the risk of computer related musculoskeletal disorders. The approach of this research project is as follows: (1) Develop a dynamic, EMG-driven musculoskeletal model of the finger and wrist, to predict the forces of, as well as to elicit the specific coordination of the finger and wrist muscles balancing the wrist and finger joint dynamics. This multilink model will incorporate Hill type muscle models and EMG to drive the distribution of forces across the muscles to determine role of finger and wrist muscles during tapping and typing. Experimental kinematic, kinetic and electromyographic (EMG) data will be used as inputs into these models. Using repeated measures experimental design, we will use the model to examine the effect of non-vertical keyswitch designs, non-neutral wrist postures, use of wrist rests, and co-contraction of finger and hand muscles on the static and dynamic loading of the wrist and fingers during tapping and typing tasks. (2) Measure and characterize the biomechanical demands of upper extremity during single finger tapping and multi-finger typing and determine how specific ergonomic interventions reduce biomechanical demands associated with these activities. We will measure the kinematics of the finger, wrist, forearm, elbow, upper arm and shoulder, the muscle activity of prime wrist, elbow and shoulder muscles, and the forces applied at the fingertip and at any forearm and/or wrist supports. Joint torques will be estimated using a link-segment model of the upper extremity and joint coordination will be determined through graphic and correlation analyses of the EMG with the segment kinematics and kinetics. We will determine which type of forearm support configurations, motor control strategies and typing styles lead to lower mechanical loading. Public Health Relevance: We will address unresolved questions about risk factors for musculoskeletal disorders among computer users, namely key angle, forearm, wrist, and palm support, wrist posture, and typing style. These biomechanical studies are a critical step in testing the effectiveness of these interventions for reducing work-related musculoskeletal disorders

Agency
National Institute of Health (NIH)
Institute
National Institute for Occupational Safety and Health (NIOSH)
Type
Research Project (R01)
Project #
5R01OH008373-03
Application #
7620007
Study Section
Safety and Occupational Health Study Section (SOH)
Program Officer
Frederick, Linda J
Project Start
2007-03-01
Project End
2011-02-28
Budget Start
2009-03-01
Budget End
2010-02-28
Support Year
3
Fiscal Year
2009
Total Cost
$245,000
Indirect Cost
Name
Harvard University
Department
Public Health & Prev Medicine
Type
Schools of Public Health
DUNS #
149617367
City
Boston
State
MA
Country
United States
Zip Code
02115
Trudeau, Matthieu B; Asakawa, Deanna S; Jindrich, Devin L et al. (2016) Two-handed grip on a mobile phone affords greater thumb motor performance, decreased variability, and a more extended thumb posture than a one-handed grip. Appl Ergon 52:24-8
Lin, Michael Y C; Young, Justin G; Dennerlein, Jack T (2015) Evaluating the effect of four different pointing device designs on upper extremity posture and muscle activity during mousing tasks. Appl Ergon 47:259-64
Onyebeke, Lynn C; Young, Justin G; Trudeau, Matthieu B et al. (2014) Effects of forearm and palm supports on the upper extremity during computer mouse use. Appl Ergon 45:564-70
Qin, Jin; Trudeau, Matthieu; Buchholz, Bryan et al. (2014) Joint contribution to fingertip movement during a number entry task: an application of Jacobian matrix. J Appl Biomech 30:338-42
Trudeau, Matthieu B; Catalano, Paul J; Jindrich, Devin L et al. (2013) Tablet Keyboard Configuration Affects Performance, Discomfort and Task Difficulty for Thumb Typing in a Two-Handed Grip. PLoS One 8:e67525
Qin, Jin; Chen, Hua; Dennerlein, Jack T (2013) Wrist posture affects hand and forearm muscle stress during tapping. Appl Ergon 44:969-76
Young, Justin G; Trudeau, Matthieu B; Odell, Dan et al. (2013) Wrist and shoulder posture and muscle activity during touch-screen tablet use: effects of usage configuration, tablet type, and interacting hand. Work 45:59-71
Trudeau, Matthieu B; Udtamadilok, Tawan; Karlson, Amy K et al. (2012) Thumb motor performance varies by movement orientation, direction, and device size during single-handed mobile phone use. Hum Factors 54:52-9
Young, Justin G; Trudeau, Matthieu; Odell, Dan et al. (2012) Touch-screen tablet user configurations and case-supported tilt affect head and neck flexion angles. Work 41:81-91
Qin, Jin; Trudeau, Matthieu; Katz, Jeffrey N et al. (2011) Biomechanical loading on the upper extremity increases from single key tapping to directional tapping. J Electromyogr Kinesiol 21:587-94

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