Date of Award

Summer 8-1-2009

Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Physical Education

First Advisor

Jeffrey Tincher

Second Advisor

Myung-Ah Lee

Third Advisor

Alfred Finch

Abstract

This study analyzed the effects of gender, strike technique, power level, and trial factors on tennis athletes performing backhand strokes with the incoming ball launched by a serving-stand. Five male and five female college tennis athletes volunteered as subjects. Each subject had 25 data points including joint centers of right and left sides for the 5th metatarsal, lateral malleolus, knees, hips, shoulders, elbows, wrists and MP joints, chin, forehead, seven points on the racket (handle, head, neck, upper right and left rims, and lower right and left rims), and the ball were recorded by two video cameras (60Hz). Each of the subjects performed 10 tennis backhand strokes in four factor combinations which were one-handed backhand stroke at maximal power level (1HMx), one-handed backhand stroke at moderate power level (1HMd), two-handed backhand stroke at maximal power level (2HMx), and two-handed backhand stroke at moderate power level (2HMd). Two video cameras with a shutter speed of 111500 sec were used to record the images of tennis backhand performances in each of the four factor combinations to be digitized. The images were digitized, transformed, and digitally filtered atl 0 Hz with the Ariel AP AS system. Overall 80 trials were selected by target area placement and ball IV velocities out of the 400 initial trials attempted. Three dependent variables shoulder, hip, and trunk rotation were calculated. ANOV As with repeated measures were used to analyze each dependent variable. Significant differences of striking technique (p=.OOO) and power level (p=.OOO) factors were found for the shoulder rotation variable. The hip rotation was significantly different during one- and two-handed backhand stroke techniques (p=.003). Significant trunk rotation differences were discovered for the gender (p=.OlO), and power (p=.007) factors. Moreover, there was a trend that approached significant differences for the effect of technique on trunk rotation at the .1 0 level. The trial factor was not significantly different in any of the dependent variables. The increases of the trunk rotation movement pose the risk of contributing lower back injuries. This study provided an analysis of both one- and two-handed backhands at maximal and moderate power level on shoulder, hip, and trunk rotation movements. The coach may apply the results of this study to create an intermediary steps in the rehabilitation process for tennis athletes who suffer from lower back condition. Moreover, we may help athletes to prevent lower back injuries by recommending proper technique or make them understand the backhand stroke mechanics.

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