BIOMECHANICAL ANALYSIS OF HAND GRIP MOTION FOR OPTIMAL HANDLE DESIGN USING A CADAVER MODEL
Open Access
- Author:
- Park, Shihyun
- Graduate Program:
- Industrial Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 26, 2009
- Committee Members:
- Andris Freivalds, Dissertation Advisor/Co-Advisor
Andris Freivalds, Committee Chair/Co-Chair
David J Cannon, Committee Member
Ling Rothrock, Committee Member
Neil Sharkey, Committee Member - Keywords:
- Hand tool design
Flexor tendon force
Grip force
Hand Biomechanics - Abstract:
- Forceful exertion of tendons while gripping hand tools may be one of the factors that lead to the development of work-related musculoskeletal disorders (WRMSDs). Also, the ratio between internal tendon force and externally applied grip force is necessary to design an optimal handle size to maximize efficiency of the force and reduce an excessive tendon force. Previous research has indicated that Flexor Digitorum Profundus (FDP) and Flexor Digitorum Superficialis (FDS) forces can be up to 3.7 times the external forces predicted by a biomechanical model. However, these values were indirect estimates derived from the biomechanical model to predict internal tendon forces. Although anatomically precise, the model was challenging to implement in practice, since they require input parameters that are often difficult or impossible to measure. Therefore, it is imperative that the model is validated with direct measurement of tendon forces using human cadaver forearms. The cadaver model with hand motion simulator allowed the application of controlled forces to the flexor tendons by the force delivery unit while the resulting grip forces are measured with force sensitive resistors. Consequently, the actual tendon forces generated by the actuators ware compared with externally applied force (grip force and finger force distribution) in power grip motion with various diameter handles. Moreover, the effect of different tendon force ratios of FDP to FDS was investigated to explore kinematic role of the ratio in power grip motion. Also, the resulting data were compared to similar measures reported in the literature and input to mathematical model to validate. Despite some differences, in general the hand motion simulator with a cadaver model produced finger kinematics closely resembling those that occur in normal human grasping and showed similar hand biomechanics result with previous studies that investigated grip force and finger force distribution with handles.