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Carvalho H.M.,Estadio Universitario Coimbra Pavilhao | Silva M.J.C.E.,Estadio Universitario Coimbra Pavilhao | Figueiredo A.J.,Estadio Universitario Coimbra Pavilhao | Goncalves C.E.,Estadio Universitario Coimbra Pavilhao | And 4 more authors.
European Journal of Applied Physiology | Year: 2011

Relationships between growth, maturation and maximal short-term power outputs were investigated in 94 youth basketball players aged 14-16 years. Data included chronological age (CA), skeletal age (SA), years of training; body dimensions, estimated thigh volume, a running based short-term exercise assessed by the line drill test (LDT), the Bangsbo sprint test (BST) and short-term muscle power outputs with the Wingate anaerobic test (WAnT). Multiple linear regression analyses were used to estimate the effects of CA, skeletal maturity (SA/CA), years of training experience, body size and lower-limb volume on short-term performance in the LDT, BST and WAnT, respectively. Explained variances differed between cycle-ergometry outputs (52-54%) and running test performances (23-46%). The independent effects of predictors were small in the fatigue scores of the WAnT (4%) and the BST (11%). Skeletal maturity, body mass and leg length were primary predictors for all maximal short-term power output measures. Leg length was more relevant as a predictor than stature in the WAnT outputs, while stature and body mass appeared in the model with the running tests as dependent variable. Maximal short-term running abilities were also sensitive to years of training. In summary, skeletal maturation, body size and thigh muscle mass explained moderate to large proportions of the variance on maximal short-term performances of adolescent basketball players. The results highlight the importance of considering maturity status in evaluating the maximal short-term power outputs of adolescent athletes. © Springer-Verlag 2010. Source


Carvalho H.M.,Estadio Universitario Coimbra Pavilhao | Coelho-E-Silva M.,Estadio Universitario Coimbra Pavilhao | Valente-Dos-Santos J.,Estadio Universitario Coimbra Pavilhao | Goncalves R.S.,Polytechnic Institute of Coimbra | And 3 more authors.
European Journal of Applied Physiology | Year: 2012

The relationships between knee joint isokinetic strength, biological maturity status and body size were examined in 14-16-year-old basketball players, considering proportional allometric modeling. Biological maturity status was assessed with maturity offset protocol. Stature, body mass, sitting height, and estimated thigh volume were measured by anthropometry. Maximal moments of force of concentric and eccentric muscular actions for the knee extensors and flexors were assessed by isokinetic dyna-mometry at 60° s -1. Regression analysis revealed a linear relation between maximal moments of force of the knee extensors in both muscular actions and knee flexors in concentric actions were moderately high (0.55 ≤ r ≤ 0.64). As for knee flexors in eccentric actions, a squared term of maturity indicator was significant indicating that the relationship with maturity offset tended to plateau approximately 2 years after PHV. Incorporating maturity indicator term with body size term (body mass or thigh volume) in the allometric models revealed that the size exponents for both body mass and thigh volume were reduced compared with simple allometric modeling. The results indicate a significant inter-individual variation in lower-limb isokinetic strength performance at 60° s-1 in concentric and eccentric muscular actions in late adolescent basketball players. The variability in performance is related to interindividual variation in estimated time before or after peak height velocity, as well as differences in body size. Proportional allometric models indicate that the influence of estimated time from age at peak height velocity on isokinetic strength performance is mostly mediated by corresponding changes in overall body mass. © Springer-Verlag 2011. Source


Carvalho H.M.,Estadio Universitario Coimbra Pavilhao | Coelho-E-Silva M.J.,Estadio Universitario Coimbra Pavilhao | Goncalves C.E.,Estadio Universitario Coimbra Pavilhao | Philippaerts R.M.,Ghent University | And 2 more authors.
Annals of Human Biology | Year: 2011

Background: Adolescence is characterized by increments in body size and physical performance. Short bursts of maximal intensity, requiring anaerobic metabolism, are important in many team sports including basketball. Aim: Variation of anaerobic power of adolescent basketball players (n = 93, 14-16 years) in relation to years before and after estimated age at peak height velocity (PHV) and variation in body size was considered. Methods: The cross-sectional study included chronological age, estimated age at PHV, training experience; stature, body mass (BM), free-fat mass (FFM) and estimated lower-limb volume (LLV) by anthropometry; and short-term power outputs derived from the Wingate Anaerobic Test (WAnT). Based on proportional allometric modeling, power outputs were partitioned for biological maturity status and size variables. Pearson correlations were used to estimate the associations between distance to PHV (maturity offset) and training experience with absolute and scaled estimates of short-term power. Results: Absolute WAnT increased linearly (PP, r = 0.72; MP, r = 0.74) through the interval of rapid growth of the adolescent spurt. Increments were related mainly to BM and muscle mass. Nevertheless, a residual significant positive influence of chronological age per se on maximal short-term power outputs remained independent of body size. Conclusion: Allometric modelling to partition size may reveal other potentially meaningful factors in the development of short-term performance in adolescent athletes. © 2011 Informa UK, Ltd. Source


Carvalho H.M.,Estadio Universitario Coimbra Pavilhao | Coelho-e-Silva M.J.,Estadio Universitario Coimbra Pavilhao | Franco S.,Estadio Universitario Coimbra Pavilhao | Figueiredo A.J.,Estadio Universitario Coimbra Pavilhao | And 6 more authors.
Applied Physiology, Nutrition and Metabolism | Year: 2012

The purpose of this study was to assess the agreement of lower-limb volume estimates based on anthropometry and dual-energy X-ray absorptiometry (DXA) as a reference method in male rugby athletes. Predictive models using body mass and skinfolds were tested to improve the relative agreement between protocols (anthropometry, DXA). Rugby players (n = 41; 19.9 ± 2.2 years) volunteered for the study. Lower-limb total and fat-free volumes were estimated by anthropometry and also derived using DXA. Cross-validation between the anthropometry technique and DXA was then performed. Lower-limb volume estimates by anthropometry overestimated reference values and tended to be further from the reference values with the increase of scale. For the total sample, standard errors of measurement for volume estimates by anthropometry were 1.99 L and 1.34 L for total and fat-free volumes, respectively. Correlations with reference values were 0.81 for lower-limb volume and 0.90 for lower-limb fat-free volume. Correlations between estimated prediction equations and reference values showed higher correlations (r = 0.96 for lower-limb volume and r = 0.93 for lower-limb fat-free volume) compared with anthropometric estimates. Overall, the agreement of anthropometry method to quantify lower-limb volumes with DXA as a reference in young adult rugby players is acceptable and is a practical method when more expensive and complex techniques are not available. The consideration of body mass and lower-limb skinfolds increases the precision of lower-limb volume estimates using anthropometry in the young adult rugby players. Source

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