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.
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.
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.
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.
The aim of the study was to compare relative body fat (% fat) in female field hockey players using several methods with dual-energy X-ray absorptiometry (DXA) as the reference. Participants were 31 ...Polish hockey players 16-30 years of age, 17 national and 14 youth level. Percent body fat was estimated by DXA (reference method), conventional and segmental bioelectrical impedance analysis (BIA), and predicted from skinfolds (SKF). National and youth team members did not differ in estimated body fat. Correlations between BIA and skinfold estimates of % fat and DXA % fat though significant, were moderate. Both % fat SKF and % fat SBIA differed significantly from % fat DXA, while estimated % fat BIA and % fat DXA did not differ. Limits of agreement were narrow for conventional BIA (-1.20 to 1.71% fat), followed by segmental BIA (3.72-6.09% fat) and broadest for SKF (5.97-9.28% fat). Differences between DXA % fat and estimated % fat with SKF and SBIA increased from the leanest to fattest athletes, whereas conventional BIA overestimated % fat relative to DXA in the small sample of individuals with low relative fatness and underestimated % fat in individuals with elevated relative fatness. Estimated % fat from conventional BIA most closely approximated DXA % fat in this sample of female field hockey players suggesting that the method may be suitable for field surveys to monitor body composition during the season.
We derive a variety of physical parameters including star formation rates (SFRs), dust attenuation and burst mass fractions for 6472 galaxies observed by the Galaxy Evolution Explorer (GALEX) and ...present in the SDSS DR1 main spectroscopic sample. Parameters are estimated in a statistical way by comparing each observed broad-band SED (two GALEX and five SDSS bands) with an extensive library of model galaxy SEDs, which cover a wide range of star formation histories and include stochastic starbursts. We compare the constraints derived using SDSS bands only with those derived using the combination of SDSS and GALEX photometry. We find that the addition of the GALEX bands leads to significant improvement in the estimation of both the dust optical depth and the star formation rate over timescales of 100 Myr to 1 Gyr in a galaxy. We are sensitive to SFRs as low as 10^{-3} M_sun/yr, and we find that low levels of star formation (SF) are mostly associated with early-type, red galaxies. The least massive galaxies have ratios of current to past-averaged SF rates (b-parameter) consistent with constant SF over a Hubble time. For late-type galaxies, this ratio on average decreases with mass. We find that b correlates tightly with NUV-r color, implying that the SF history of a galaxy can be constrained on the basis of the NUV-r color alone. The fraction of galaxies that have undergone a significant starburst episode within the last 1 Gyr steeply declines with mass-from ~20% for galaxies with ~10^8 M_sun to ~5% for ~10^11 M_sun galaxies.
The respiratory infection COVID-19 caused by the virus SARS CoV-2 has continued to be a major health problem worldwide and has caused more than a million mortalities. Even if the development of ...COVID-19 vaccines has shown much progress, efforts to find novel, natural anti-viral drugs should be pursued. Halymenia durvillei is a marine red alga widely distributed around Southeast Asia. This study aimed to develop new anti SARS CoV-2 compounds from ethanolic and ethyl acetate extracts of H. durvillei via a computational approach, focusing onthe inhibitory action against the main protease (3CL-Mpro). In this study, 37 compounds were extracted and identified by GC–MS analysis. The potentials of compounds 1–2 tetradecandiol and E,E,Z-1,3,12-nonadecatriene-5,14-diol were identified for therapeutic purposes based on our pharmacophore study, while cholest-5-En-3-Ol (3.Beta.)- had a high fitness score in molecular docking studies both in monomer and dimer state compared to the N3 inhibitor and remdesivir affinity scores. As these compounds show competitive affinity scores against the 3CL-Mpro, these natural compounds may be effective for the treatment of COVID-19 infection. The ADME and pharmacokinetic studies should also be employed to assess the ability of the natural compounds as oral drugs. These promising results have shown the potentials of H. durvillei as an alternative drug in addressing COVID-19 infection. Accordingly, further studies should explore the effectiveness of these active compounds.
To estimate the biological maturity status of youth football players 9-14 yr old using a noninvasive method and to compare the body size of players of contrasting status.
Subjects were members of ...youth football teams in two central Michigan communities. Height and weight were measured on 653 boys 8.7-14.6 yr. Heights of biological parents of 582 boys were reported and subsequently adjusted for overestimation. Decimal age, height, and weight of the player and midparent height were used to predict mature (adult) height for the boy. Current height of each player was expressed as a percentage of his predicted mature height to provide an estimate of biological maturity status. Percentage of predicted mature height of each boy was expressed as a z-score to classify players into maturity groups. ANCOVA, controlling for age, was used to compare body size in contrasting maturity groups.
Mean percentages of predicted mature height of the players matched those of longitudinal reference samples, but there was a trend for higher percentages among older players, suggesting advanced maturation. Overall, 405 boys were classified as on time/average in maturity status (69.6% 95%CI 65.7-73.3), 154 were classified as early/advanced (25.5% 95%CI 23.0-30.3), and only 23 were classified as late/delayed (3.9% 95%CI 2.6-6.0). The gradient for height, weight, and BMI was as follows: early > on time > late, and differences were greater for weight and the BMI than for height.
Percentage of predicted mature height attained at a given age appears to be a reasonable indicator of maturity status. The method needs to be validated with other more direct indicators (skeletal age, sexual maturation) and applied to other samples.
The purpose of the current study was to assess the developmental changes in change of direction and dribbling speed in youth soccer players taking into account skeletal age (SA), maturity status, ...body size, estimated fat mass, aerobic endurance, lower limb explosive strength and annual volume of training.
Eighty-three male soccer players aged 10-15 years (SA) at baseline were annually followed over 5 years, resulting in an average 4.4 observations per player. After testing for multicollinearity, multi-level regression modeling was used to examine the longitudinal developmental changes on change of direction and dribbling speed.
Maturity-associated variability was significant in change of direction and also dribbling speed among young soccer players aged 12-14 years with better scores being performed by late maturers. Moreover, the predicted longitudinal scores for change of direction and dribbling speed improved with SA (P<0.01), SA2 (P<0.01) and skeletal maturity status entered as an additional developmental predictor (P<0.05). Estimated fat-free mass (P<0.01), aerobic endurance (P<0.01) and lower limb strength (P<0.01) were additional predictors in both models. The soccer-specific skill, dibbling speed, was also explained by annual volume of training (P<0.05).
Skeletal maturity status explains inter-individual variability on maximal short-term run performances with and without the ball possession at early ages of participation in competitive soccer. The effects tend to persist across ages combined with longitudinal changes in body composition and functional fitness. In the particular case of the ball test, annual volume of training was also a longitudinal performance predictor.
We report on the development and implementation of analytical methodology for investigating elemental accumulation in different layers within plant leaves, with in-situ spatial resolution mapping, ...exploiting the technique of LIBS. The spectrochemical analysis of lead-doped leaf samples is demonstrated to develop a real time identification procedure in order to complement other analytical techniques not lending themselves for spatial resolution analysis. Our findings suggest that with elevated levels of Pb within the plants transportation and storage of some nutrition elements is changed.
The stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood was examined. The sample included 76 males and 71 females measured between the ages of 8 and 18 ...years and again as young adults (12 year follow-up). Indicators included the sum of three trunk skinfolds (SF3), mean blood pressure (MBP), and fasting blood glucose (GLY), high-density lipoprotein cholesterol (HDL-C), ratio of total cholesterol to HDL-C (CHOL/HDL), and triglycerides (TG). The indicators were subjected to principal components analysis to obtain a composite risk factor index (RFI). Partial interage correlations, controlling for initial age and length of follow-up, were 0.70 and 0.50 for SF3, 0.40 and 0.54 for MBP, 0.58 and 0.56 for HDL-C, 0.51 and 0.57 for CHOL/HDL, 0.37 and 0.20 (NS) for TG, 0.30 and 0.14 (NS) for GLY, and 0.51 and 0.46 for the RFI, in males and females, respectively. The results indicate that indicators of the metabolic syndrome are moderately stable from childhood and adolescence into young adulthood.
Knowledge of population patterns of physical activity levels and musculoskeletal fitness are important in the selection of appropriate target groups for public health interventions.
To examine the ...stability of physical activity levels and musculoskeletal fitness in the Canadian population.
The sample included 951 male and 958 female subjects, aged 11-69 yr, for whom the appropriate measurements were available in the 1981 Canada Fitness Survey and its 7-yr follow-up, the Campbell's Survey. Participants were divided into 2-yr age groups in childhood (11-18 yr) and 10-yr age groups in adulthood (19-69 yr). Measures of physical activity were estimated activity energy expenditure (AEE) and time spent on activity, whereas indicators of musculoskeletal fitness consisted of sit-ups, push-ups, grip strength, and sit-and-reach (trunk flexibility).
7-yr inter-age correlations ranged from -0.08 to 0.39 for AEE, -0.10 to 0.33 for time on activity, 0.42 to 0.80 for sit-ups, -0.07 to 0.73 for push-ups, 0.44 to 0.82 for grip strength, and 0.47 to 0.85 for sit-and-reach. In general, significant tracking correlations for physical activity levels were limited to adulthood, whereas significant tracking of musculoskeletal fitness was observed at all ages for all indicators except push-ups. Male subjects exhibited greater stability in push-ups than female subjects. The average percentage of participants remaining in the lower and upper quintiles of the distribution over 7 yr was greater for musculoskeletal fitness (36-68%) than for physical activity level (30-34%).
Physical activity level is not a very stable characteristic in the Canadian population; however, indicators of musculoskeletal fitness are moderately stable over 7 yr.
Investigated the reliability and validity of the Borg and OMNI rating of perceived exertion (RPE) scales in adolescent girls during treadmill exercise. Girls were randomly assigned to one of the RPE ...scales during various treadmill exercise conditions. Results indicated that the OMNI cycle pictorial scale was reliable and valid for use with adolescent girls. It appeared to be more reliable and valid than the Borg scale in this population. (SM)
PDF
