William G. Thorland

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.

Prevalence of coronary heart disease risk factors in active children, 7 to 12 years of age.

Forty-seven active boys and girls, 7 to 12 years of age, underwent a comprehensive medical and physical evaluation in order to assess their prevalence of single and multiple coronary heart disease risk factors. Each subject received a densiometric determination of body composition, blood lipid analysis, pulmonary function and a physical work capacity test to assess their peak oxygen consumption (Vo2max). Obesity (greater than 25% fat), elevated triglycerides (greater than 100 mg %) and the presence of Type IV hyperlipoproteinemia appear to be the more predominant risk factors. Twenty-nine (62%) of the children had at least one risk factor. Of these, seventeen had two or more risk factors with one subject having as many as five factors.

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...

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 ...

Anthropometric and body build variables as discriminators of event participation in elite adolescent male track and field athletes

Abstract The purpose of this study was to determine the extent to which anthropometric and body build measures discriminated between elite adolescent male athletes competing in different track and field events. One hundred and six national‐level Junior Olympic male athletes (mean age ± s.d. = 17.7±0.7 yr) volunteered as subjects. The sample included 26 middle distance runners, 24 sprinters/hurdlers, 39 jumpers and 17 throwers. The body build variables measured included fat‐free body weight/height (FFB/Ht), the sum of 6 skinfolds (SUM‐SF), the sum of 12 diameters (SUM‐D), the sum of 11 circumferences (SUM‐C), biacromial diameter/bi‐iliac diameter (BA/BI) and the bidimensional somatotype rating components X (ectomorphic rating—endomorphic rating) and Y [twice the mesomorphic rating — (endomorphic+ ectomorphic rating)]. Multiple discriminant analysis revealed three significant (P<0.05) discriminant functions (DF1, DF2, DF3). Validation of the discriminant functions revealed an overall value of 76.8% of subje...

Comparison of Peak Performance Measures in Children Ages 6 to 8, 9 to 10, and 11 to 13 Years.

Abstract The purpose of this study was to assess differences in peak performance measures between three different age groups: 6 to 8 years, 9 to 10 years, and 11 to 13 years. Each child underwent a progressive maximal bicycle test. Measures such as oxygen consumption ([Vdot]O2), ventilation ([Vdot]E BTPS), heart rate (HR), respiratory exchange ratio (R), and work rate were continuously monitored. Peak cardiac output ([Qdot]), stroke volume (SV), and arteriovenous oxygen difference a-v O2 diff) were indirectly determined during the last 15 sec of exercise using a CO2 rebreathing method. Peak measures for [Vdot]O2 (1/min), [Vdot]E BTPS (1/min), and work rate (kpm/min) increased with age such that each was statistically different (p > .05) among age groups. No statistical differences among age groups were found for [Vdot]O2 (ml/kg body wt/min), R, [Qdot], SV, and a-v O2 diff. It was concluded that peak [Vdot]O2 (1/min) differs among age groups in young children but not when expressed in ml/kg body wt/min. In...

Cardiac Dimensions in Elite Young Track Athletes.

The purpose of the study was to compare young sprint and distance runners for changes in their cardiac dimensions with increased age (10–17 years) or body surface area (1–2 m2). Echocardiographic dimensions were obtained on 73 male track athletes competing in the 1983 National Age Group Track and Field Association championships. Each group of athletes was also compared with a hypothetical normal population (matched for weight and age) generated from prediction equations derived by Henry, Gardin, & Ware (1980). The cardiac dimensions examined were: Left ventricular internal diameter, left ventricular posterior wall thickness, and interventricular septum thickness. The male distance runners (n = 38) had a significantly greater increase in left ventricular posterior wall thickness and interventricular septum thickness with increasing age or increasing body surface area compared to the sprinters (n = 35) or compared to the predicted normal population. The left ventricular internal diameter was not significant...