Maximum oxygen uptake (VO2max) and body composition have been shown to deteriorate with age. How much of the decline is attributable to aging and how much is affected by reduced physical activity is not known. The purpose of this investigation was to determine the aerobic capacity and body composition of 24 master track athletes and to evaluate the relationship to age and maintenance of training over a 10-yr period. The subjects (50-82 yr of age) were retested after a 10.1-yr follow-up (T2). All continued their aerobic training, but only 11 were still highly competitive (COMP) and continued to train at the same intensity. The other 13 athletes studied became noncompetitive (post-COMP) and reduced their training intensity. The results showed the COMP group to maintain its VO2max and maximum O2 pulse while the post-COMP group showed a significant decline (54.2-53.3 vs. 52.5-45.9 ml X kg-1 X min-1; 20.7-20.8 vs. 22.4-20.0 ml/beat from test one (T1) to T2 for the COMP vs. post-COMP groups, respectively). Maximum heart rate declined 7 beats/min for both groups. Body composition showed no difference between groups from T1 to T2. For both groups body weight declined slightly (70.0-68.9 kg), percent fat increased significantly (13.1-15.1%), and fat-free weight decreased significantly (61.0-59.0 kg). Thus, when training was maintained, aerobic capacity remained unchanged over the follow-up period. Body composition changed for both groups and may have been related to aging and/or the type of training performed.

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The purpose of this study was to evaluate the effectiveness of resistance training performed either 2 days/week or 3 days/week. One hundred and seventeen sedentary volunteers were randomly assigned to one of the two training groups or a control group. Twenty-two men (27 +/- 5 years) and 22 women (26 +/- 5 years) trained for 10 weeks. Twenty-five men (26 +/- 5 years) and 22 women (24 +/- 5 years) trained for 18 weeks. Twenty-six subjects served as controls and did not train. Training consisted of a single set of variable resistance bilateral knee extensions performed to volitional fatigue with a weight load that allowed seven to ten repetitions. Prior to and immediately following training, isometric strength was evaluated at 70, 85, 100, 115, 130, 145, 160, and 171 degrees of knee extension with a Nautilus knee extension tensiometer. All groups who trained showed a significant increase in peak isometric strength when compared with controls (P less than 0.01). Groups that trained 3 days/week increased peak isometric strength (10 weeks = 21.2%; 18 weeks = 28.4%) to a greater extent (P less than 0.05) than groups that trained 2 days/week (10 weeks = 13.5%; 18 weeks = 20.9%). We conclude that resistance training 2 days/week significantly improves knee extension isometric strength; however, the magnitude of strength gain is greater when training is performed 3 days/week. These data indicate that the adult exerciser (18 to 38 years) training 2 days/week may derive approximately 80% of the isometric strength benefits achieved by those training 3 days/week.

B-mode ultrasound was used to measure fat and muscle thicknesses on 30 subjects (17 men, 13 women, age = 20-37 yr) at 14 sites (triceps, biceps, forearm, chest [males only], subscapular, axilla, abdomen, suprailium, lumbar, quadriceps, suprapatellar, hamstrings, medial calf, and posterior calf) on two different days. Quadruplicate photographic images (trials) were printed from a single measurement at each site on each day. Two investigators each measured two of the images from each site. Each thickness was measured to the nearest 0.05 mm with a vernier caliper. Generalizability theory was used to determine the relative contribution of subjects, investigators, days, and trials to the total measurement variability. Subjects accounted for 84-96% of the variance in the muscle measurements and for 79-97% of the variance in the fat measurements. A subjects-by-day interaction accounted for 2-13% of the variance in muscle measurements and 2-12% of the variance in fat measurements. The contribution by investigators and trials to the variance was less than 1%. Generalizability coefficients (G) exceeding 0.92 were obtained for all sites for muscle measurements, while G for fat measurements exceeded 0.90 for all but the axilla site (G = 0.88). These results indicate that B-mode ultrasound is a highly reliable method for the measurement of both fat and muscle thicknesses in young males and females. © 1992 Wiley-Liss, Inc.

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