Title

Development and validation of a multi-segment computerized model for children's overhand throw

Date of Award

2004

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Ergonomics

First Committee Member

Shihab Asfour, Committee Chair

Abstract

The research herein, presents the development of a computerized model to analyze the overhand throwing motion. The model is written in Bodybuilder Language, for application in the VICON motion capture system. This model enables detailed analysis of defined body segments, angles between segments and body motions during the overhand throw.The set-up to collect the data is a "state-of-the-art" motion capture system located in the Biomechanics Lab at the University of Miami. This system enables the capture of the position of reflective markers attached to the body, along with asynchronous recording of three-dimensional ground forces through a set of force plates.The model was used and validated with three applications. The first application of the model is an analysis of the impact on velocity of the stride leg extension towards the target, as well as an analysis of the subject's ability to follow a series of instructions. The results of the analysis show that although the subjects were not able to follow the instructions well, the stride leg extension impacts ball velocity by a factor of .0251 miles per hour for each millimeter of landing leg extension towards the target.The second application of the model presents an analysis of the contribution of absolute velocity by each of the joints of the body. The key findings for this application uncovered significant differences between the velocity contribution of the fingers, the wrist and the elbow joints, across the different children skill level groups. Children that have a higher skill level with the overhand throwing process, generate significantly more contribution to velocity from their upper extremities, than children at a lower skill level.The third application of the model is an analysis of the ground reaction forces at the beginning of the overhand throw and at the point of release. Statistical significance on the impact to the resulting ball velocity was found for the initial push-off force in the "X" direction and on the landing stride "Z" leg force. Additionally, the weight of the subject was also found to impact the resulting ball velocity.

Keywords

Engineering, Industrial; Health Sciences, Recreation; Biophysics, General

Link to Full Text

http://access.library.miami.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3159147