Systematic training for sport may be an additional factor, among others, that infl uences components and relationships among the components of body composition.Abstract: Absolute and relative components of body mass are a primary focus in studies of body composition. Components change with growth and maturation, requiring care in selecting methods of assessment in children and adolescents. Although sex differences are apparent in fat-free mass (FFM), fat mass (FM), and relative fatness (% Fat) during childhood, they are more clearly defined during adolescence and adulthood. Body composition is one of many determinants of sport performance, but % Fat tends to be the primary focus of discussion in young athletes. The influence of training for sport on bone mineral has received more attention in recent years because of methodological advances in assessment and concern for potential negative effects of altered menstrual function on bone. Relative fatness of young athletes in several sports is summarized, and issues related to sport training and body composition in young athletes are considered. Suggestions for dealing with body composition in young athletes are provided.

Growth in peak VO2 exhibits a clear growth spurt in both sexes during adolescence. The growth spurt occurs earlier in females but is of greater magnitude in males.

Positional differences have been examined in women's basketball, field hockey, netball, and volleyball, but not in elite women's ice hockey. Our purpose was to describe and compare physical, fitness, and skating performance characteristics of forwards (F), defensemen (D), and goalies (G). Subjects were 112 University of Alberta women players (21.4 +/- 2.9 years of age). A full anthropometric battery was conducted on each player. Heath-Carter anthropometric somatotypes were calculated. Percent body fat (%fat) was estimated from both general and population-specific equations. Subjects performed off-ice fitness tests (vertical jump, 40-yd dash, Leger test for predicting .V(O2)max) and on-ice fitness (Modified 3-Repeat Sprint Skate Test-MRSS, blood lactate after sprint test) and skating performance tests (6.10-m acceleration test, Cornering S-Turn Agility Test). Descriptive statistics and multivariate analyses of variance were run using SPSS (Version 10.0) for the MacIntosh, with a significance level set a priori at p < 0.05. Significant positional differences were found for bicristal breadths (D > G, F > G); relaxed arm circumference (D > F, G > F); supraspinale and biceps skinfolds (G > D, G > F); and endomorphy (G > F). Significant differences among positions were also found for the MRSS (G > D > F) and agility tests (G > D, G > F). D tended to have the most robust build overall. F were leaner than D and G, and their smaller relaxed arm circumference measurements most likely reflect less subcutaneous fat on the upper arm. F had greater anaerobic power than D, followed by G, and they tended to have greater aerobic capacity. F and D were more agile than G. Performance demands appear to be position specific. F need to be the most versatile and fit because of a greater amount and variety of work performed both during practices and games; their required degrees of versatility and fitness are followed by those required of D and G.

Girls actively training in sport (n=23) and girls not active in sport (n=26) were compared in terms of ages at peak height velocity (PHV) and menarche, the interval between ages at PHV and menarche, and ages at attaining stages of pubic hair and breast and the estimated duration of the stages. Subjects were longitudinally followed from about 11-18 years of age. Stature and weight were measured and stages of pubic hair and breast development were rated at approximately quarterly intervals between the initial observation and 14 years of age, at semiannual intervals until 16 years, and at irregular intervals subsequently. Age at menarche was obtained prospectively. The active girls trained 12 hours per week in rowing, track and swimming for an average of 3.9+/-1.2 years during puberty and the growth spurt. Longitudinal stature records for individual girls were fitted with kernel regression to estimate age at PHV (years). The interval between age at PHV and age at menarche was calculated. Ages at appearance of pubic hair and breast stages 3, 4 and 5 were calculated by back-interpolation, while intervals between stages 3 and 4 were calculated after log 10 transformation. Peak height velocity and menarche occur, on average, slightly later in girls active in sport, but the differences are not significant. The interval between PHV and menarche, PHV (cm/year), ages at attaining pubic hair and breast stages 3, 4 and 5, and estimated intervals between adjacent stages also do not significantly differ between girls actively training in sport and those not active in sport. Thus, regular training in sport during puberty and the adolescent spurt does not apparently influence the timing and progression of somatic and sexual maturation in girls.

Results of three longitudinal studies of the growth, maturation and fitness of youth active in sport are summarized. Data include size attained and growth rates for height and body mass, secondary sex characteristics, skeletal age, age at peak height velocity, and two indicators of fitness, peak O2 uptake and power output at a heart rate of 170 bpm (PWC 170). The data for active youth are compared to local reference data and where appropriate to data from other European longitudinal studies. Allowing for variation in methodology and sampling, regular training in sport during puberty and the adolescent spurt does not influence size attained, growth rate, and the timing and progression of somatic, sexual and skeletal maturation in boys and girls. Active and nonactive boys and girls, respectively, do not differ significantly in the mean age at maximum growth in power output at a heart rate of 170 bpm. Boys active in sport, however, have a greater maximal gain in submaximal power output than nonactive boys. Analysis of ontogenetic allometry of peak oxygen uptake and stature and body mass indicate variation between individuals, and between boys of contrasting maturity status.

No abstract

Doing peer review has been effectively implemented to help students develop critical reading and writing skills; however, its application in Human Physiology programs is limited. The purpose of the present study was to determine the impact of peer review on Human Physiology majors' perceptions of their scientific literacy and writing skills. Students enrolled in the Scientific Writing course completed multiple writing assignments, including three revisions after receiving peer and instructor feedback. Students self-assessed their knowledge, skills, and attitudes related to science and writing in pre- and postcourse surveys (n = 26 with complete data). Seven survey items related to scientific literacy and writing skills impacted by peer review were selected for analysis. Scores on these survey items were summed to form a composite self-rating score. Responses to two questions regarding the most useful learning activities were submitted to frequency analysis. Mean postcourse scores for individual survey items and composite self-rating scores were significantly higher than precourse means (P < 0.05). Peer review was the most frequently noted among 21 learning activities for increasing scientific literacy and in the top 5 for improving writing skills. In conclusion, peer review is an effective teaching/learning approach for improving undergraduate Human Physiology majors' knowledge, skills, and attitudes regarding science and scientific writing.

The purpose of this study was to compare percent fat (% Fat) estimates from anthropometric equations using skinfolds (SKF) in women's ice hockey players to estimates obtained from Lunar iDXA. Data were collected on 19 elite female Swedish hockey players (mean age ± SD = 18.4 ± 2.4 y). Four skinfolds (SKF) (triceps, abdominal, suprailiac, and thigh) were measured within two hours of iDXA assessments. The % Fat estimates from iDXA and four anthropometric equations were compared using paired t-tests, and a one-way ANOVA was used to compare % Fat estimates from the anthropometric equations. Bland Altman analyses were used to assess agreement between % Fat estimates from SKF and iDXA. The significance level was set a priori at p<0.05. The % Fat estimates from anthropometric equations were significantly lower than those from iDXA (mean ± SD: 26.85 ± 4.93%, p=0.000). Bland Altman analyses indicated mean differences of -7.96 to -10.13 percentage points between anthropometric equations and iDXA. Estimates of % Fat from anthropometric equations (range: 16.72% to 18.89%) were within the range reported in earlier studies using the Sum of 7 SKF. Thus, SKF offer a reasonable alternative to iDXA for this population, but result in underestimates of % Fat relative to iDXA. Strength and conditioning coaches should use the same body composition assessment method consistently, and interpret the results with caution, as they are estimates and not true values.