Biomedical subjects

R M Malina

Publications and source records attributed to R M Malina.

At least 19 recordsLinked to original sources

PubMed2000

Cardiac dimensions, physical activity, and submaximal working capacity in youth of the Québec Family Study.

The relationships between cardiac dimensions and physical activity and submaximal working capacity were examined in 198 boys and 154 girls, aged 9-18 years, who were participants in the first phase of the Québec Family Study. The sample was divided into three age groups, 9-12 years, 13-15 years, and 16-18 years. Indicators of physical activity included estimated daily energy expenditure (EE) and time spent in moderate-to-vigorous physical activity (median metabolic equivalents of energy expenditure above resting metabolic rate >/=4.8). Submaximal physical working capacity (PWC(150)) was determined using a submaximal exercise test on a Monark cycle ergometer. Echocardiographically determined dimensions included posterior wall thickness, septal wall thickness, and left ventricular mass (LVM). The analyses were based on partial correlation and analysis of covariance, controlling for age and body surface area. Relationships between EE/physical activity variables and cardiac dimensions were low and, at best, moderate (r < 0.45). With subjects grouped into tertiles by indicators of physical activity, LVM was significantly different only among 16- to 18-year-old girls (157 g vs 134 g in the highest and lowest quartiles, respectively; P < 0.05). Correlations between cardiac dimensions and PWC(150) were also low (r < 0.30), with few significant relationships. In general, cardiac dimensions were not related to habitual physical activity and PWC(150) in young subjects aged 9-18 years. However, significant correlations were positive, as expected. LVM may be related to submaximal power output in boys since it accounts for 3% of the variance, after adjusting for age and BSA.

Adolescent↗

PubMed2000

Growth and overweight of Navajo youth: secular changes from 1955 to 1997.

OBJECTIVE: To examine the growth status, prevalence of risk of overweight and of overweight, and secular changes in growth status in Navajo youth from 1955 to 1997. SUBJECTS: 526 (256 males, 270 females) Navajo children 6-12 y of age. MEASUREMENTS: Stature and mass were measured and the body mass index (BMI) was calculated. ANALYSIS: All three variables were plotted relative to age- and sex-specific US reference data and the prevalence rates for risk of overweight and of overweight were estimated using the BMI as the criterion. The cut-off for the risk of overweight was the age- and sex-specific 85th and 95th percentiles of NHANES I, while the cut-off for overweight was a BMI>/=95th percentiles. Age-specific sex differences were compared using independent samples t-tests. Secular changes for body size were estimated by comparing age- and sex-specific means for stature, mass, and the BMI in the present study and two previous studies in 1955 and 1989. RESULTS: No statistically significant differences were observed between sexes within age groups. In both sexes, mean age-specific stature appeared to be relatively stable around the 50th percentile of US reference values. Mean age-specific mass appeared to be relatively stable between the 50th and 90th percentiles of the reference values, while the mean BMI tended to fluctuate about the 85th percentile. Approximately 41% of the Navajo boys and girls 6-12 y of age had BMIs >/=85th percentiles of US reference data. Compared to corresponding data on Navajo youth in 1955 and 1989, the current sample was larger in mass and the BMI. The estimated rate of secular change in mass was about 1.5 kg/decade in younger boys and girls, and about 3 kg/decade in older boys and girls between 1955 and 1997. The estimated rate of secular change in the BMI was about 0.5-1.0 units/decade between 1955 and 1997, while that for stature was about 2 cm/decade between 1955 and 1997. CONCLUSIONS: The results are consistent with recent findings on the Navajo Health and Nutrition Survey that overweight is a serious public health concern across the lifespan in the Navajo, and that the problem begins in childhood. Furthermore, Navajo children appear to be heavier than about a decade ago. International Journal of Obesity (2000) 24, 211-218

Arizona↗

PubMed1999

Body size and physique among Canadians of First Nation and European ancestry.

The purpose of this study was to compare body size and physique among Canadians of Aboriginal (First Nation [FN]) and European ancestry (EA) from the northern Ontario communities of Temagami and Bear Island. The sample consisted of 130 FN and 494 EA participants including adults (20-75 years: 214 men, 234 women) and youth (5-19 years: 97 boys, 79 girls). Indicators of body size and physique included stature, the sitting height-to-stature ratio (SSR), body mass, BMI, estimated upper-arm muscle area, biacromial, bicristal, biepicondylar, and bicondylar breadths, and the Heath-Carter anthropometric somatotype (endomorphy, mesomorphy, and ectomorphy). There were few differences in body size between FN and EA, with the exception of adult females. Adult FN females were significantly heavier and had greater bone breadths than EA women (P < 0.001). On the other hand, somatotype differed significantly between EA and FN by age and sex, except for 5-19-year-old females. Among boys and men, FN had greater endomorphy (P < 0.03), whereas FN men also had lower ectomorphy (P < 0.01). Among women, FN were significantly more endomorphic and mesomorphic and less ectomorphic (P < 0.001). Although results for 5-19-year-old females were not significant, they were in the same direction as the other groups (greater endomorphy). Forward stepwise discriminant function analyses indicated that endomorphy was the most important discriminator between FN and EA by age and sex.

Adolescent↗

PubMed1999

Physical activity, physical fitness, and coronary heart disease risk factors in youth: the Québec Family Study.

OBJECTIVE: The relationships between physical activity, fitness, and CHD risk factors were investigated in 342 males and 268 females 9-18 years of age. METHODS: Daily energy expenditure, moderate to vigorous physical activity, inactivity, and television viewing time were estimated. Indicators of physical fitness included submaximal work capacity, quadriceps muscle strength, sit-ups, and the sum of six skinfolds. Risk factors included mean arterial blood pressure and fasting blood levels of triglycerides, LDL-cholesterol, HDL-cholesterol, and glucose. RESULTS: Canonical correlations between activity and risk factor profiles range from 0.22 to 0.45, while those between fitness and risk factor profiles range from 0.34 to 0.55, indicating that 5 to 20% and 11 to 30% of the variance in the risk profile is explained by activity and fitness, respectively. CONCLUSION: The results suggest that both physical fitness and level of habitual physical activity are strongly associated with CHD risk factors in this sample of youth.

Adolescent↗

PubMed1999

Physique, subcutaneous fat, adipose tissue distribution, and risk factors in the Québec Family Study.

OBJECTIVE: To investigate the relationships among subcutaneous fatness, subcutaneous adipose tissue (SAT) distribution, somatotype and risk factors for coronary heart disease (CHD). SUBJECTS: The sample included 1410 (715 male and 695 female) youths and adults from the Quebec Family Study. MEASUREMENTS: Six skinfolds and the dimensions necessary for the derivation of the Heath-Carter anthropometric somatotype (endomorphy, mesomorphy, ectomorphy) were measured. The six skinfolds were summed to provide an index of subcutaneous adiposity (SUM). In addition, the trunk-to-extremity skinfold ratio, adjusted for SUM using regression procedures (TER), and the first principal component (PC1) of skinfold residuals (also adjusted for SUM) were used to indicate SAT distribution, independent of the overall level of fatness. Risk factors for CHD included systolic and diastolic blood pressures, and fasting glycaemia, triglycerides (TGs), plasma cholesterol, high and low density lipoprotein (HDL-C and LDL-C) cholesterol, and the HDL-C/total cholesterol (CHOL) ratio. RESULTS: In general, SUM was positively correlated with endomorphy and mesomorphy, and negatively correlated with ectomorphy. On the other hand, SAT distribution was not associated with somatotype, except in females where TER and PC1 were negatively correlated with mesomorphy. Results of forward stepwise regression analyses to predict CHD risk factors, indicated that a significant proportion of the variance in the risk factors could be accounted for by SUM, SAT distribution and somatotype (up to 16%). SUM is the best predictor, entering the regressions first (most important) in six of 15 significant regressions in males and 14 of 16 significant regressions in females. Somatotype components enter as predictors 10 times in males, and six times in females. Similarly, TER and PC1 enter as predictors nine times in males and five times in females. CONCLUSIONS: Somatotype is related to SUM, while somatotype and SAT distribution are largely independent of one another. Furthermore, SUM, somatotype and SAT distribution are significant predictors of biological risk factors for CHD.

Adipose Tissue↗

PubMed1999

Seven-year stability of indicators of obesity and adipose tissue distribution in the Canadian population.

BACKGROUND: The prevention of obesity appears to be a better approach than treatment; thus, the prediction of future obesity from current status is important. OBJECTIVE: The aim of the study was to examine the stability of adiposity and adipose tissue distribution (ATD) in the Canadian population. DESIGN: The sample included 1048 males and 1063 females aged 7-69 y at baseline from the Campbell's Survey, a 7-y follow-up of the Canada Fitness Survey. Indicators of adiposity included body mass index (BMI), sum of 5 skinfold thicknesses (SF5), and waist circumference (Waist), whereas indicators of ATD included the ratio of trunk to extremity skinfold thicknesses adjusted for SF5 (TER(adj)), and Waist adjusted for BMI (Waist(adj)). RESULTS: Interage correlations ranged from 0.53 to 0.91 for BMI, from -0.09 to 0.72 for SF5, from 0.24 to 0.89 for Waist, from 0.23 to 0.73 for TER(adj), and from 0.18 to 0.77 for Waist(adj). Correlations for BMI were higher than for SF5, suggesting that fat-free mass may contribute to the stability of BMI. Although lower than those for BMI, correlations for indicators of ATD were significant, indicating a propensity to retain an android or gynoid pattern. Furthermore, the average percentage of participants remaining in the lower or upper quintiles for the various indicators ranged from 37.8% to 66.7% in males and from 47.0% to 65.3% in females, indicating that those in the lower and upper portions of the distribution tend to remain there. CONCLUSION: Obesity and ATD showed significant stability over 7 y in the Canadian population.

Adipose Tissue↗

PubMed1999

Validity of the body mass index as an indicator of the risk and presence of overweight in adolescents.

The validity of the body mass index (BMI) as an indicator of the risk of becoming overweight and of the presence of overweight was evaluated in 6 groups of adolescents comprising several ethnic groups (n = 1570, aged 9-19 y). With use of triceps skinfold thickness and estimated percentage body fat as the criteria for adiposity, BMI had high specificities (86.1-98.8% for risk of overweight and 96.3-100% for presence of overweight) and lower but variable sensitivities (4.3-75.0% for risk of overweight and 14.3-60% for presence of overweight). Thus, almost all adolescents who were not at risk for overweight or who were not overweight were classified correctly. In contrast, many adolescents who were at risk of overweight or who were overweight were not correctly identified as measured by BMI. Partial correlations, controlling for age, between BMI and the triceps skinfold thickness and estimated percentage body fat were generally moderate to moderately high, whereas BMI and triceps skinfold thickness appeared to be equally related to estimated total body fatness and percentage body fat in Mexican American and Austrian white males. BMI was better correlated with trunk skinfold thicknesses, but when relative subcutaneous fat distribu-tion was statistically controlled, the trunk-extremity contrast in the correlations was no longer apparent.

Journal Article↗

PubMed1999

Childhood and adolescent physical activity patterns and adult physical activity.

PURPOSE: A major research priority is the influence of childhood and adolescent physical activity patterns on adult physical activity. The research in this area is inconsistent. Therefore, the purpose of this study was to evaluate the relationships among specific components of physical activity during childhood and adolescence and exercise habits in adulthood. METHODS: We analyzed preteen and teenage experiences, individual and team sports, and several psychosocial variables. One hundred and five male volunteers completed questionnaires about their current (estimated energy expenditure (EE)) and historic physical activity and a treadmill stress test. RESULTS: Based on correlations and regression analyses, without and with controlling for potentially confounding variables (treadmill run time and sum of skinfolds), the frequency of being forced to exercise and the frequency of being encouraged to exercise during the preteen years were inversely related to adult physical activity. Being forced to exercise during the preteen years was more related to participation in individual sports than to participation in team sports or both individual and team sports. CONCLUSIONS: Being forced to exercise during childhood may have potentially negative consequences for later activity. The findings indicate that experiences related to participation in activity during childhood and adolescence may influence adult physical activity. The implications of our findings are discussed and future research is recommended.

Adolescent↗

PubMed1999

Ulnar variance and skeletal maturity of radius and ulna in female gymnasts.

UNLABELLED: It is has been suggested that repetitive loading on the distal end of the radius in elite gymnasts may lead to epiphyseal changes, a premature closure (union) of the radius growth plate, and ulnar overgrowth. PURPOSE: It is hypothesized that ulnar overgrowth in female gymnasts is associated with advanced maturity status and early onset of epiphyseal closure of the radius, and later maturity status and later onset of epiphyseal closure of the ulnar. METHODS: Posterior-anterior radiographs of 201 female gymnasts, participants of the 1987 World Championships Artistic Gymnastics, were used to measure ulnar overgrowth, to determine skeletal maturation of the hand and wrist with the Tanner-Whitehouse technique, and to determine the maturity status of the radius and ulna separately, particularly with regard to the onset of epiphyseal closure. To test the hypothesis, extreme quintiles for ulnar overgrowth were contrasted for skeletal maturation of the hand and wrist and for maturity stages of the radius and ulna as defined by the Tanner-Whitehouse criteria. RESULTS: Female gymnasts who demonstrate ulnar overgrowth are skeletally more advanced in maturity status of the entire hand-wrist compared with gymnasts who did not show ulnar overgrowth. There were, however, no differences between gymnasts in the extreme quintiles of ulnar overgrowth in the maturation of the radius, although gymnasts with ulnar overgrowth show more advanced maturity status of the ulna. CONCLUSIONS: Ulnar overgrowth is thus not apparently associated with advanced maturity of the distal radial epiphysis as defined in protocols for assessing skeletal maturity and does not apparently lead to premature epiphyseal closure of the distal radius.

Adolescent↗

PubMed1999

Potential effects of ethnicity in genetic and environmental sources of variability in the stature, mass, and body mass index of children.

We examined sources of variability in stature, body mass, and body mass index (BMI) in families of black and white elementary schoolchildren from Philadelphia, Pennsylvania. The sample consisted of 445 black and 379 white children, 7-13 years old, and their parents (total n = 2016). The sample was distributed among 596 nuclear families, each representing an independent pedigree. Maximum-likelihood-based variance decomposition methods were used to simultaneously estimate ethnic group-specific effects of genes, sex, age by sex, and unmeasured environmental factors on stature, body mass, and BMI. Likelihood ratio tests were performed to assess the significance of h2 estimates and differences in sigma g and sigma e between black and white families. Genes account for moderate proportions of the phenotypic variance (h2) of these traits in black and white children. In black and white children, respectively, h2 estimates were 0.37 and 0.53 for stature, 0.37 and 0.31 for body mass, and 0.38 and 0.24 for BMI (p < 0.0005). Although the differences in h2 between ethnic groups were not significant (stature, p = 0.23; body mass, p = 0.49; BMI, p = 0.14), black children exhibited a significantly greater total residual phenotypic standard deviation (sigma e and sigma g) in body mass and BMI and a significantly greater sigma e for stature compared with white children. The larger residual phenotypic variance in the black sample is likely due to exposure to unmeasured environmental factors that are not accounted for in this model. Given that sigma g for stature is not significantly different between ethnic groups, the slightly lower estimates in black children are due to the increased contribution of the environment to the phenotypic variance in this trait.

Adolescent↗

PubMed1999

The contribution of anthropometric characteristics to performance scores in elite female gymnasts.

BACKGROUND: Aims of this study were: a) to identify anthropometric variables correlated with gymnastic performance, and b) to predict performance scores from a combination of anthropometric dimensions. METHODS EXPERIMENTAL DESIGN: correlational analysis and a stepwise multiple regression were used. SETTING: Subjects were participants at the 24th World Championships Artistic Gymnastics, Rotterdam, The Netherlands, in 1987. PARTICIPANTS: A total of 168 female gymnasts (mean age: 16.5 +/- 1.8 years) were investigated. Each gymnast participated in all events. MEASURES: An extensive battery of anthropometric dimensions was taken on each athlete. The somatotype was estimated. Skeletal maturation of the hand-wrist was assessed. Competition scores for the four individual gymnastic events (balance beam, floor exercise, vault, uneven bars) and a composite score for each gymnast were the dependent variables. RESULTS: Moderately high, significant correlations (p < 0.01) were observed between skinfolds and endomorphy, and gymnastics performance scores, r varying from -0.38 to -0.60, for biceps skinfold and the score on balance beam, and for endomorphy and the total score, respectively. The correlations suggest that gymnasts with more subcutaneous fat and higher endomorphy have lower performance scores. About 32% to 45% of the variance in gymnastic performance scores could be explained by anthropometric dimensions and/or derived variables, but endomorphy and chronological age are the most important predictors. CONCLUSIONS: There is a relatively strong relationship between several anthropometric variables and gymnastic performance in a sample of elite female gymnasts, but the associations are not sufficiently high to predict performance scores on an individual basis.

Adolescent↗

PubMed1998

Television viewing, physical activity, and health-related fitness of youth in the Québec Family Study.

PURPOSE: To evaluate the relationships among television viewing time (TVTIME), physical activity, and health-related fitness in youth 9-18 years of age from the Québec Family Study. METHODS: The sample included 423 males and 361 females 9-18 years of age from the greater Québec city area. TVTIME, daily energy expenditure (EE), and moderate to vigorous physical activity (MVPA) were estimated. Four health-related fitness variables were tested: knee extension strength, physical work capacity at 150 beats x min(-1), situps, and sum of skinfolds. The body mass index (BMI) was also included. Relationships were assessed using correlations and analysis of covariance. RESULTS: Correlations between TVTIME and EE and MVPA were low and not significant, with no pattern by age group and gender. Those between TVTIME and fitness variables were also low and generally not significant, with no pattern by age and gender. Adolescents in the highest and lowest quartiles of TVTIME showed no consistent differences in EE, MVPA, and the four fitness items. Similarly, adolescents in the highest and lowest quartiles of EE, MVPA, and each fitness item did not consistently differ in TVTIME. CONCLUSIONS: The results indicate that time watching television has only a weak association with indicators of physical activity and health-related fitness in Québec youth. Since the data are from the early 1980s, generalizations to more current samples should be tempered with care.

Adolescent↗

PubMed1998

Univariate and multivariate genetic analysis of subcutaneous fatness and fat distribution in early adolescence.

Univariate and multivariate analyses of the genetic and environmental contributions to variance in adipose tissue and adipose tissue distribution were carried out in early adolescents. Stature, weight, body mass index (BMI), and five subcutaneous skinfolds were measured at half-yearly intervals in 105 MZ and DZ twin pairs from 10 to 14 years. The most parsimonious model, which provided an adequate explanation for variation in the BMI, five skinfolds, and the T/E ratio, included additive genetic and specific environmental factors. Multivariate analyses of the genetic architecture of subcutaneous fat indicated a general skinfold genetic factor, an extremity skinfold genetic factor, and skinfold specific genetic factors. This implies that all skinfolds are under control of the same set of genes, that a different set of genes partly controls extremity skinfolds, and that other genes have a small skinfold specific impact. Environmental contributions included a general skinfold environmental factor and skinfold specific environmental factors. BMI is under control of the same set of genes as skinfolds and shows high genetic correlations with trunk skinfolds, which implies that nearly the same genes may influence trunk skinfolds and the BMI. All models were fairly consistent across the age range.

Adipose Tissue↗

PubMed1998

Obesity and relative subcutaneous fat distribution among Canadians of First Nation and European ancestry.

OBJECTIVE: To compare Canadians of Aboriginal (First Nation, FN) and European ancestry (EA), with respect to obesity, subcutaneous fatness and relative subcutaneous fat distribution. DESIGN: Cross-sectional comparison. SUBJECTS: 118 First Nation and 472 European ancestry Canadians from Northern Ontario, youth (5-19 y) and adults (20-75 y). MEASUREMENTS: Stature, mass and skinfold thicknesses at the triceps, biceps, medial calf, subscapular, suprailiac and abdominal sites. ANALYSIS: Prevalence of obesity was determined using the 85th percentile of body mass index (BMI) from NHANES II as the cut-off. Principal components (PC) analyses were performed on the six skinfolds. The first component (PC1) represented a trunk-extremity skinfold contrast. Differences in mean component scores between FN and EA were assessed using independent samples t-tests. RESULTS: Prevalence of obesity among FN was high, ranging from 29% in youth to 60% in adult females. FN demonstrated greater subcutaneous adiposity and greater values for PC1, with the exception of adult males, where the difference is in the expected direction, but is not significant. The direction of the differences indicates that the FN have a greater centralization of subcutaneous fat. CONCLUSIONS: FN Canadians generally have a greater prevalence of obesity, greater subcutaneous fatness and a more centralized distribution of body fat than those of European ancestry.

Adipose Tissue↗

PubMed1998

Physical activity and health-related fitness in youth: a multivariate analysis.

PURPOSE: To evaluate the relationship between indicators of physical activity and health-related fitness in youth 9-18 yr. METHODS: A cross-sectional sample of 356 boys and 284 girls 9-18 yr of age from phase I of the Quebec Family Study was studied. The sample was divided into three age groups by gender, 9-12, 13-15, and 16-18 yr of age. Physical activity variables included two estimates of activity, estimated daily energy expenditure (EE) and estimated moderate-to-vigorous physical activity (MVPA), and one estimate of inactivity, time spent watching television per day (TVTIME). Health-related fitness variables were the sum of six skin folds (SUM), number of sit-ups in 1 min (SITUP), physical work capacity at 150 beats x min(-1) (PWC150), and static strength of the leg (LMS). Partial canonical correlation was used to quantify the relationship between standardized (z-transformed) activity variables and health-related fitness items, controlling for age. RESULTS: There is a weak to moderate association between physical activity and fitness in youth. The first activity canonical variate is a function of positive loadings for EE and MVPA, with a smaller, negative loading for TVTIME. The first fitness variate generally includes positive loadings for PWC150 and SITUP, with a small negative loading for the SUM and a small positive loading for LMS. The first canonical correlations indicate that the variance shared by the fitness and activity variates ranges from 11 to 21%. CONCLUSION: There is a significant relationship between activity and health-related physical fitness, but a large part of the variability (80-90%) in fitness is not accounted for by physical activity as measured in this study.

Adolescent↗

PubMed1997

Skeletal maturation, somatic growth and physical fitness in girls 6-16 years of age.

The importance of chronological age (CA) and skeletal age (SA) in explaining variation in somatic dimensions, and the independent contributions of CA, SA, stature (ST) and weight (WT) to variability in physical fitness were investigated in a sample of 6593 girls 6-16 years of age. Body dimensions included lengths, breadths, circumferences, skinfolds, and Heath-Carter somatotype, while fitness tests included measures of health- and performance-related fitness, and cardiovascular and lung functions. Age-specific correlations were calculated between SA and anthropometric dimensions, fitness tests and cardiovascular and lung functions, while age-specific stepwise multiple regressions were used to investigate the relative importance of SA, CA, ST and WT in explaining fitness and cardiovascular and lung functions. SA is most highly correlated with lengths and then with breadths, circumferences and skinfolds in this order. SA per se or in interaction with CA is the only significant predictor of somatic characteristics. Among fitness items, physical working capacity and static strength correlate highest with SA. Bent arm hang, leg lifts and sit-ups correlate negatively with SA but values are low, while all other components correlate at non-significant or low levels. Results of the multiple regression analysis indicate that, with few exceptions, CA, SA, ST and WT and their interactions explain less than 10% of the variance in most physical fitness items. However, for PWC, arm pull strength, and bent arm hang, the interaction terms explain between 12% and 67% of the variance.

Adolescent↗

PubMed1997

Development and tracking in fitness components: Leuven longtudinal study on lifestyle, fitness and health.

In the Leuven Growth Study of Belgian Boys the growth and physical performance of Belgian boys followed longitudinally between 12 and 19 years were studied. Subsequently, a subsample (n = 240) of Flemish-speaking males were reexamined at 30 and 35 years. A first question relates to the individual growth patterns in a variety of physical fitness characteristics. The three strength tests (static, functional, explosive) show curves that are qualitatively similar to those for height and weight. Their adolescent spurts occur after the height spurt. Flexibility and the two speed tests appear to reach maximum velocities prior to the height and weight spurts. Longitudinal principal component analysis was applied to the study of growth patterns of several somatic and motor characteristics. The results for height show three components sufficient to provide an adequate representation of the original information. The first component characterizes the general position of an individual growth curve. Components 2 and 3 reflect fluctuation in percentile level during the age period studied and can be conceived as indices of stability and are related to age at peak height velocity (APHV) and peak height velocity (PHV), respectively. Relationships between somatic characteristics, physical performance, and APHV have been studied in a sample of 173 Flemish boys, measured yearly between +/- 13 and +/- 18 years and again as adults at 30 years of age. The sample was divided into three contrasting maturity categories based on the APHV. There are consistent differences among boys of contrasting maturity status during adolescence in body weight, skeletal lengths and breadths, circumferences, and skinfolds on the trunk. There are no differences in skinfolds on the extremities. None of the differences in somatic dimensions and ratios among the three contrasting maturity groups are significant at 30 years of age except those for subscapular skinfold and the trunk/extremity skinfold ratio. During adolescence, speed of limb movement, explosive strength and static strength are negatively related to APHV; thus, early maturers performed better than late maturers. However, between late adolescence and adulthood (30 years), the late maturers not only caught up to the early maturers, but there were significant differences for explosive strength and functional strength in favor of late maturers. Finally, age-specific tracking, using inter-age correlations, of adult health- and performance-related fitness scores were investigated. In addition, the independent contribution of adolescent physical characteristics to the explanation of adult fitness scores was also studied. Tracking between age 13 and age 30 years was moderately high (46% of variance explained) for flexibility, low to moderate (between 19% and 27% of variance explained) for the other fitness parameters and low for pulse recovery and static strength (7% to 11% of variance explained). Between age 18 and age 30 years the tracking was high for flexibility, moderately high for explosive and static strength, and moderate for the other fitness parameters except for pulse recovery. The amount of variance of adult fitness levels explained increased significantly when other characteristics observed during adolescence entered the regressions or discriminant functions.

Adolescent↗

PubMed1997

Prospective and retrospective longitudinal studies of the growth, maturation, and fitness of Polish youth active in sport.

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.

Adolescent↗