Perceptual and Mofor Skilk, 1992, 75, 363-366.
O Perceptual and Motor Skills 1992
GRIP STRENGTH AND FATIGUE IN JUNIOR COLLEGE TENNIS PLAYERS ' ALAN M. KRAMER AND DUANE V. KNUDSON Baylor University Summary.-Change in grip strength over 30 trials was documented in two samples of junior college tennis players to assess possible fatigue. Eight men and eight women performed 30 maximum-grip strength tests with 25-sec. rests between trials. Significant positive correlations (.38 and .53 for men and women) were observed between grip strength and trials. In practical terms, grip strength did not change over 30 trials in these tennis players. The data suggested that the repetitive gripping patterns used by these players in tennis play resulted in consistent maximum-grip strengths across 30 trials.
Although there is a common understanding of the importance of gripping the racket in tennis, little research has been conducted to document the effects of fatigue on grip strength in relation to playing tennis. Research on grip and forearm strength in tennis has focused on arm dominance and potential relationships to tennis elbow (Chim, Priest, & Kent, 1974; Stratford, Norman, & McIntosh, 1989; Strizak, Gleim, Sapega, & Nicholas, 1983). Even the Sport Science Department of the United States Tennis Association only evaluates a single trial of grip strength when collecting data for their Player Development Program (USTA, 1992). Grip fatigue patterns in normal subjects have been shown to be decreasing linearly (Reddon, Stefanyk, Gill, & Renney, 1985) and logarithmically (Montazer & Thomas, 1991). Researchers have shown that despite specificity of training, muscular strength and endurance are related (Anderson & Kearney, 1982; Clarke & S t d , 1970). The purpose of this study was to evaluate how grip strength changes when skilled tennis players performed 30 tests of grip strength with rests similar to tennis play.
METHOD Sixteen players from two nationally ranked junior college tennis teams gave informed consent for the study. Eight women and men were tested over a two-week period during preseason training for spring competition. The men had a mean age of 20.3 1.8 yr. and mean weight of 158 16 Ib. The women's mean age and weight were 18.9 0.6 yr. and 132 k 19 Ib. Grip strength was measured with an Owl Biomedical No. 3001 grip dynamometer. Dynamometer reliability was checked by suspended weights. The dynamometer gripspan was set at 4.5 cm for men and 4.25 cm for women to match actual racket grip dimensions more closely.
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'Address enquiries to D. V. Knudson, Ph.D., Department o [ Health, Physical Education, and Recreation, Baylor University, POB 97313, Waco, TX 76798.7313.
364
A. M. KRAMER & D. V KNUDSON
The testing protocol of Montazer and Thomas (1991) was modified to simulate tennis play. Subjects held the dynamometer in the dominant hand, with the arm at the side, and squeezed with maximum effort for a count of three seconds. The dynamometer reading was recorded. Thirty maximum grips were performed with 25-sec. rest intervals between trials. This rest interval corresponds to typical times between points in tennis play (Jacobson, 1991; Kibler, 1992). Grip strengths (kg-force) were averaged across subjects for the men and women separately. Linear regression and correlations were performed on mean grip strengths versus trials.
RESULTS A N D DISCUSSION The largest trial mean grip strengths for the men and women were 47.6 + 6.2 and 30.5 + 4.5 kg, r e s p e ~ t i v e l y .Trial ~ mean grip strengths were consistent with previous research on skilled players (Chinn, et al., 1974; Elliott, Ackland, Blanksby, Hood, & Bloomfield, 1989; Powers & Walker, 1982). Fig. 1 illustrates the mean strength data across trials and the regression line for the eight women. A significant Pearson correlation ( r = 0.53; t = 3.9, p
O Perceptual and Motor Skills 1992
GRIP STRENGTH AND FATIGUE IN JUNIOR COLLEGE TENNIS PLAYERS ' ALAN M. KRAMER AND DUANE V. KNUDSON Baylor University Summary.-Change in grip strength over 30 trials was documented in two samples of junior college tennis players to assess possible fatigue. Eight men and eight women performed 30 maximum-grip strength tests with 25-sec. rests between trials. Significant positive correlations (.38 and .53 for men and women) were observed between grip strength and trials. In practical terms, grip strength did not change over 30 trials in these tennis players. The data suggested that the repetitive gripping patterns used by these players in tennis play resulted in consistent maximum-grip strengths across 30 trials.
Although there is a common understanding of the importance of gripping the racket in tennis, little research has been conducted to document the effects of fatigue on grip strength in relation to playing tennis. Research on grip and forearm strength in tennis has focused on arm dominance and potential relationships to tennis elbow (Chim, Priest, & Kent, 1974; Stratford, Norman, & McIntosh, 1989; Strizak, Gleim, Sapega, & Nicholas, 1983). Even the Sport Science Department of the United States Tennis Association only evaluates a single trial of grip strength when collecting data for their Player Development Program (USTA, 1992). Grip fatigue patterns in normal subjects have been shown to be decreasing linearly (Reddon, Stefanyk, Gill, & Renney, 1985) and logarithmically (Montazer & Thomas, 1991). Researchers have shown that despite specificity of training, muscular strength and endurance are related (Anderson & Kearney, 1982; Clarke & S t d , 1970). The purpose of this study was to evaluate how grip strength changes when skilled tennis players performed 30 tests of grip strength with rests similar to tennis play.
METHOD Sixteen players from two nationally ranked junior college tennis teams gave informed consent for the study. Eight women and men were tested over a two-week period during preseason training for spring competition. The men had a mean age of 20.3 1.8 yr. and mean weight of 158 16 Ib. The women's mean age and weight were 18.9 0.6 yr. and 132 k 19 Ib. Grip strength was measured with an Owl Biomedical No. 3001 grip dynamometer. Dynamometer reliability was checked by suspended weights. The dynamometer gripspan was set at 4.5 cm for men and 4.25 cm for women to match actual racket grip dimensions more closely.
*
*
*
'Address enquiries to D. V. Knudson, Ph.D., Department o [ Health, Physical Education, and Recreation, Baylor University, POB 97313, Waco, TX 76798.7313.
364
A. M. KRAMER & D. V KNUDSON
The testing protocol of Montazer and Thomas (1991) was modified to simulate tennis play. Subjects held the dynamometer in the dominant hand, with the arm at the side, and squeezed with maximum effort for a count of three seconds. The dynamometer reading was recorded. Thirty maximum grips were performed with 25-sec. rest intervals between trials. This rest interval corresponds to typical times between points in tennis play (Jacobson, 1991; Kibler, 1992). Grip strengths (kg-force) were averaged across subjects for the men and women separately. Linear regression and correlations were performed on mean grip strengths versus trials.
RESULTS A N D DISCUSSION The largest trial mean grip strengths for the men and women were 47.6 + 6.2 and 30.5 + 4.5 kg, r e s p e ~ t i v e l y .Trial ~ mean grip strengths were consistent with previous research on skilled players (Chinn, et al., 1974; Elliott, Ackland, Blanksby, Hood, & Bloomfield, 1989; Powers & Walker, 1982). Fig. 1 illustrates the mean strength data across trials and the regression line for the eight women. A significant Pearson correlation ( r = 0.53; t = 3.9, p
