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Fasting plasma lipid and lipoprotein concentrations were determined in 25 men and 25 women (mean ages 42 and 39 yr respectively) whose exclusive mode of regular exercise was tennis play. When compared to a sedentary group matched for age, sex, and education, the tennis players exhibited similar plasma total cholesterol and LDL-cholesterol concentrations and significantly lower triglyceride and VLDL-cholesterol concentrations. Plasma HDL-cholesterol was significantly higher in the tennis players (57.8 +/- 13.9 versus 46.2 +/- 12.0 mg/100 ml in the men and 73.9 +/- 12.3 versus 61.7 +/- 13.3 mg/100 ml in the women). When we simultaneously controlled for age, relative weight, cigarette smoking, alcohol intake, and oral contraceptive use (in females), the significance of the difference in plasma HDL-cholesterol as well as triglyceride and VLDL-cholesterol concentrations was unaffected in the males but substantially reduced in the females. It is concluded that frequent tennis playing is associated with increased plasma HDL-cholesterol concentrations and that this relationship is independent of other factors known to alter plasma HDL-cholesterol concentration.

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Cardiorespiratory characteristics, relative body fat, grip strength and selected skinfolds, circumferences and bone diameters were determined in 25 males and 25 females (31--55 yr) whose exclusive mode of regular exercise was tennis (9.7--11.1 hr/wk). Mean resting heart rates were 54 beats/min for the males and 61 beats/min for the females. Mean resting blood pressures were 117/75 and 107/68 mmHg for the males and females, respectively. Compared to normally active populations of the same age and sex, the tennis players displayed an above average maximal oxygen uptake (mean values equal 50.2 ml/kg.min-1 for the males and 44.2 ml/kg.min-1 for the females), below average relative body fat (mean values equal 19.3% and 20.3% for the males and females, respectively), greater dominant grip strengths, and similar non-dominant grip strengths. The results indicate that either physically superior individuals choose to play tennis, or that regular tennis participation produces above average levels of fitness, or both.

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This study investigated the efficacy of free-wheel bicycling and tennis as endurance conditioning activities. The subjects were 38 sedentary, middle-aged male volunteers, who were randomly assigned to one of four groups: bicyling (N=9); tennis (N=10); jogging (N=9); and control (N=10). Each subject was tested twice at the beginning and once at the conclusion of the 20-week study. Each training group exercised 3 days/week for 30 min/day, following 15 minutes of formal warm-up. The bicycling, tennis and jogging groups had an average attendance of 3.0, 2.7, and 2.8 days/week, and maintained theri exercise intensity at 83, 65, and 85% of HR max respectively. Using analysis of covariance, only the bicycle and jogging groups significantly increased treadmill Vo2max (14.8 and 13.3% respectively) even though there was a 5.7% improvement for the tennis group. The control group did not change. Vo2max was also assessed on a cycle ergometer for the bicycle and jogging groups, and increased significantly by 17.4 and 14.0% respectively, thus, specificity of the training response was not identified. VEmax increased significantly in the bicycling and jogging groups, while resting blood pressure did not change for any of the four groups. Relative to body composition, only the bicycle group increased lean body weight. The bicycle and jogging groups had substantial decreases in relative and absolute body fat, but these changes were not statistically significant due to changes in the control group. In conclusion, bicycling and jogging appear to provide comparable physiological benefits. Tennis produced only modest increases in endurance capacity but, since the duration of each training session was only 30 to 50% of a typical time period for playing tennis, the results of the present study may, in fact, be underestimating changes in Vo2max due to the interaction of intensity and duration in facilitating change.

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This paper describes a modification of the standard oxygen-dilution technique for determining residual lung volume, whereby rapid responding oxygen and carbon dioxide analyzers are used to determine the point of nitrogen equilibration, and a five-liter rebreathing bag is substituted for the standard spirometer. This simplified method reduced the total test time to five min or less for duplicate determinations, and eliminated the need for a nitrogen analyzer and a spirometer. This method was found to be both reliable (r = 0.99) and valid (r = 0.92), with a standard error of prediction of 125 ml, and a mean difference of only eight ml, when compared with the established oxygen-dilution technique on a sample of 76 healthy men and women, 19 to 55 years of age. In a subsample of 13 subjects, residual volume was also determined with the nitrogen washout technique, which correlated r = 0.89 and r = 0.91 with the established and modified oxygen-dilution techniques respectively. The use of assumed values for the initial and final alveolar concentrations of nitrogen did not appear to significantly influence the final results.

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The metabolic cost of circuit weight training was determined in a group of 20 men and 20 women, 17 to 36 years of age, who volunteered to participate in this study. Performing 3 circuits (10 stations/circuit), using a work (30-sec) to rest (15-sec) ratio of 2:1, and a total exercise time of 22.5 min, the energy expenditure was found to be highly related to body weight (r = 0.84 and r = 0.67 for men and women respectively). The average gross energy expenditure was 539.7 and 367.5 kcal/hr. (9.0 and 6.1 kcal/min) for the men and women respectively, but was 7.0 and 6.0 kcal/kg-hr when expressed relative to body weight, and 8.1 and 8.2 kcal/kg(LBW)-min when expressed relative to lean body weight. Thus, when body composition was considered, there were essentially no differences in the energy expenditure for males and females.

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The efficacy of a 10-week program of circuit weight training to elicit specific physiological alterations was evaluated in a group of men (n = 16) and a group of women (n = 12), with an additional group of men (n = 10) and a group of women (n = 11) serving as controls. The circuit consisted of 10 stations performed on a Universal Gym, 3 circuits per day (approximately 22.5 min/day), 3 days/week. The subjects exercised at 40-55% of 1-RM, executing as many repetitions as possible in 30 sec on each of the lifts, followed by a 15 sec rest as the subject moved to the next station. Following the training program, the experimental groups demonstrated significant increases in lean body weight, flexed biceps girth, treadmill endurance time, VEmax (women only), Vo2max in ml/kg-min (women only), flexibility and strength. Significant decreases were found in selected skinfold measurements, and in resting heart rate (control group showed similar decreases). No change was found in body weight or in relative or absolute body fat. Generally, the women exhibited equal or greater changes when compared to the men for all variables assessed, which could be a function of their lower initial starting levels, or a more intense training program. It was concluded that circuit weight training is a good general conditioning activity, i.e., attends to more than one component of fitness.

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