Gerald D. Tharp

The effect of exercise intensity and duration on salivary immunoglobulin A.

SummaryTwo experiments were performed to examine salivary immunoglobulin A (s-IgA) responses to varying levels of exercise intensity and duration. For experiment 1, 9 college men (mean age, SD=23.56, 1.64 years) completed treadmill runs of 15, 30, and 45 min at approximately 60% of maximum oxygen consumption (VO2max). For experiment 2, 9 other college men (mean age, SD=23.67, 2.0 years) ran for 20 min at approximately 50, 65 and 80% of VO2max. Unstimulated salivary samples were collected before, and immediately, 1 and 2 h after the exercise. Samples were assayed for s-IgA using an enzyme-linked immunosorbent assay. Mean s-IgA levels did not change significantly (P>0.05) at any of the post-exercise collection times when compared to pre-exercise levels. The results of this investigation indicated that running at intensities of 50–80% of VO2max and for durations of 15–45 min did not affect s-IgA levels.

Body composition and somatotype characteristics of junior Olympic athletes.

Body composition and somatotype were determined in Junior Olympic competitors to evaluate the structural characteristics concomitant to high proficiency in various athletic activities. Underwater weighings and anthropometric determinations of somatotype were performed on 145 male and 133 female adolescent participants in national meet competition in the sports of track and field, gymnastics, diving, and wrestling. The most frequent differences within either the male or female Junior Olympic samples involved the performers in throwing events (shot put, discus, and javelin), who were taller, heavier, fatter, and of unique somatotype when compared to all or most other competitors. Additional structural differences, generally of a lesser magnitude, also existed between other groups of Junior Olympians. Differences in body composition characteristics were also noted when Junior Olympians were compared with other adolescent athletes or non-athletes.

Basketball exercise and secretory immunoglobulin A

SummaryThis study examined saliva levels of immunoglobulin A (IgA) before and after three games and three practice sessions during the basketball season. Saliva was collected from 27 prepubescent boys (10–12 years) in a small Fry league and 23 postpubescent boys (16–18 years) on a high school varsity team. Saliva samples were frozen for later assay using a standard enzyme-linked immunosorbent assay technique. IgA levels were significantly increased after games 1 and 3 in both age groups and after practice 3 in the high school athletes. Over the 2 months of saliva collections the pre-exercise IgA increased significantly with games 2 and 3 higher than game 1, and practice 3 higher than practices 1 and 2, in both age groups. These results indicate that basketball exercise can increase saliva IgA levels and that chronic exercise over the basketball season may increase the resting levels of IgA. These changes may give athletes more protection against respiratory infections both after exercise and in the resting state later in the season.

Validity of anthropometric equations for the estimation of body density in adolescent athletes.

One hundred forty-one adolescent male (age: X +/- SD = 17.43 +/- 0.96 yr) and 133 adolescent female (16.51 +/- 1.39 yr) athletes were studied to determine the validity of available anthropometric equations for estimating body density (BD). Anthropometric measures were taken of eight skinfolds, nine circumferences, and four diameters. Body density, determined by underwater weighing (corrected for residual lung volume), was 1.080 +/- 0.010 g X ml-1 for the males and 1.066 +/- 0.010 g X ml-1 for the females. Cross-validation of 17 selected equations on the males revealed validity coefficients ranging from R2 = 0.29-0.67 and total-error scores ranging from 0.0062-0.0277 g X ml-1. Among the females, cross-validation of 15 selected equations revealed validity coefficients ranging from R2 = 0.31-0.67 and total-error scores ranging from 0.0064-0.0214 g X ml-1. While equations of either linear or quadratic form demonstrated acceptable accuracy in the estimation of male BD values, only quadratic equations displayed similar levels of accuracy among the females. Based on these results, as well as consideration of characteristics related to inter-tester error and the variance of predicted scores, the quadratic equations of Jackson and Pollock, Lohman, and Pollock et al., as well as the linear equation of Forsyth and Sinning, were found to be particularly appropriate for the estimation of BD in adolescent athletes.

Strength and anaerobic responses of elite young female sprint and distance runners.

The purpose of this study was to assess the strength and anaerobic responses of elite young female runners, in order to determine the relationship of these characteristics to age and high proficiency in sprint events. Thirty-one national junior-level sprint and middle distance runners were evaluated for isokinetic peak torque for leg extension at velocities ranging for 30 degrees to 300 degrees X s-1, anaerobic power and capacity based on the Wingate test, and body composition based on underwater weighing. Age-related and event-related differences were noted for both the peak torque and anaerobic response measures. Peak torques were greater for the older (greater than 11.67 yr) runners and greater for the sprinters when measured at the higher testing velocities. Anaerobic power and capacity were also greater for the older runners, but event-related differences only appeared when anaerobic power was adjusted for fat-free weight (adjusted anaerobic power was greater in the older sprinters). These results indicate that both age and fat-free weight influence strength and anaerobic responses in young female runners and that exceptional levels of such characteristics only appear for sprinters within the upper age groups of youth competition.

Comparison of Sprint and Run Times with Performance on the Wingate Anaerobic Test

Abstract In recent years the classic Margaria step-test for anaerobic power has been largely replaced by bicycle ergometer tests, the most popular of these being the Wingate Anaerobic Test (WAnT). The purpose of this study was to examine the relationship between the WAnT and sprint-run times and to determine the influence of age and weight on the WAnT scores. The 56 male volunteers (age 10–15 years) recruited from a track club and junior high school represented a wide range of athletic abilities. Subjects were tested for anaerobic power (5 sec output) and capacity (30 sec output) using the Wingate test procedures. Wingate scores for anaerobic power and capacity were only moderately correlated with 50 yd dash times (r = −.53 and −.53) and with the 600 yd run (r = −.26 and −.29). Partial correlations between these variables were lower when age adjusted and higher when adjusted for body weight. Results of this study indicate that the Wingate anaerobic test is only a moderate predictor of dash or run times, b...

Factors affecting the estimation of physical working capacity at the fatigue threshold

The purpose of this study was to investigate potential improvements in the methodology associated with the Physical Working Capacity at the Fatigue Threshold (PWCFT) test including: (1) the use of a continuous test protocol; (2) the use of a treadmill; (3) the use of a bipolar EMG lead system for noisy electronic environments; and (4) the potential for residual fatigue from tests repeated 24 hours apart. The results of the continuous test protocol (mean +/- S.D. = 210 +/- 73 watts) correlated well (r = 0.856) with the original discontinuous technique (222 +/- 83 watts) and there was no significant (p greater than 0.05) difference between the mean values (t = 1.146). Treadmill testing required a bipolar lead system to counteract the electrical noise generated by the treadmill motor. The heart rate values which corresponded to PWCFT on the treadmill (mean +/- s.d. = 164 +/- b.p.m.) and bicycle ergometer (153 +/- 18 b.p.m.) were highly correlated (r = 0.833) and there was no significant (p greater than 0.05) difference between the mean values (t = 2.22). The use of a bipolar lead EMG system on the bicycle ergometer resulted in significantly (p less than 0.05) smaller voltage for any given power output, and the PWCFT exhibited a low to moderate correlation (r = 0.60) with PWCFT derived from a unipolar arrangement. The test-retest results of discontinuous PWCFT measurements performed 24 hours apart on the bicycle ergometer were correlated at r = 0.812 with no significant (p greater than 0.05) difference (t = 0.52) between the mean values (test = 198 +/- 60; retest = 191 +/- 63 watts).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic exercise and cardiac vascularization

SummaryMale albino rats were trained on a motorized treadmill for 8 weeks, using eight training regimens which varied in severity from 0.313 m·s−1, 3 days/week for 30 min each day, to 0.447 m·s−1, 5 days/week for 60 min each day. At the end of the 8 week training period, the animals were anesthetized and Pelikan ink infused retrogradely through the aorta, into the coronary arteries and capillaries of the heart. The hearts were sectioned, stained and examined for the number of capillaries per mm2and the capillary/muscle fiber (C/F) ratios. Six of the eight exercise groups had capillary densities significantly lower than the density in the sedentary control group of 3,022 cap mm−2. Likewise, five of the exercise groups had significantly lower C/F ratios than the sedentary group ratio of 1.077. The difficulties inherent in identification of cardiac muscle fibers make the C/F ratio a weaker measurement for determining cardiac vascularity. The lower capillary density in the trained hearts could be produced by muscle fiber hypertrophy which would push the capillaries farther apart. It is concluded that exercise training does not stimulate the multiplication of cardiac capillaries. The beneficial effect of exercise on the heart is probably a result of enlargement of the coronary arteries or the collateral circulation.

Isokinetic leg flexion and extension strength of elite adolescent female track and field athletes

Abstract Sixty-two elite adolescent (age: 16.39 ± 1.62 yrs) female track and field athletes volunteered to be measured isokinetically for peak torque of the leg flexors and extensors. The sample included 16 throwers, 11 jumpers, 12 middle-distance runners (> 400 m), and 23 sprinters. A Cybex II isokinetic dynamometer was used to measure dominant leg strength at 180°/sec. One-way ANOVA revealed significant between group differences for absolute flexion and extension (Nm), extension/body weight (Nm/Kg), and extension/lean body weight (Nm/Kg). Scheffe post-hoc comparisons showed that, for absolute leg extension strength, throwers were stronger than middle-distance runners (by 54.4%), sprinters (35.6%), and jumpers (23.6%). For absolute leg flexion movements, throwers were stronger than middle distance runners (37.4%) and sprinters (32.1%). Jumpers had greater extension peak torque values than middle-distance runners relative to body weight (14.0%), and throwers were stronger than middle-distance runners for ...

The effect of glycogen depletion and supercompensation on the physical working capacity at the fatigue threshold

SummaryThe purpose of this investigation was to determine the effect of glycogen depletion and super-compensation on the physical working capacity at the fatigue threshold (PWCFT). Ten adult males (mean age 23 years, SD 3) volunteered as subjects for this study. During the first laboratory visit the subjects performed a maximal bicycle ergometer test for the determination of maximum oxygen consumption