scholarly journals Assessment of Reliability in Isokinetic Testing Among Adolescent Basketball Players

Medicina ◽  
2011 ◽  
Vol 47 (8) ◽  
pp. 446 ◽  
Author(s):  
Humberto Carvalho ◽  
Manuel Coelho E Silva ◽  
Enio Ronque ◽  
Rui Gonçalves ◽  
Renaat Philippaerts ◽  
...  
Keyword(s):  
Body Size ◽  
Knee Flexion ◽  
Knee Extension ◽  
Peak Height ◽  
Height Velocity ◽  
Isokinetic Strength ◽  
Peak Height Velocity ◽  
Training Experience ◽  
Basketball Players ◽  
Isokinetic Testing

Background. The reproducibility of day-to-day testing of isokinetic concentric and eccentric muscular actions among adolescent basketball players aged 14 to 16 years and relationships of mean within-subject variation in two isokinetic testing sessions with chronological age, biological maturation (estimated age at peak height velocity), training experience, body size, lower-body morphology, and initial strength performance were evaluated. Material and Methods. The sample included 27 basketball players who completed replicate test sessions of 5 repetitions of reciprocal concentric and eccentric knee extensions and flexions at 60º s–1. A randomly selected subsample of 8 players completed a third testing session to confirm reliability estimates. Results. Coefficients of variation (CV) between sessions 1 and 2 ranged from 8.1% to 17.4%, and intraclass coefficients (ICCs) ranged from 0.72 to 0.89. For sessions 1 and 3, CVs ranged from 3.9% to 6.0%, and ICCs ranged from 0.95 to 0.99. The initial level of strength of eccentric knee flexion (r=–0.43) and eccentric knee extension (r=–0.42) were correlated (P<0.05) with eccentric knee extension within-variation between two sessions. Training experience (r=–0.37, P<0.05) and initial values of concentric knee flexion (r=–0.62, P<0.01) were correlated with concentric knee flexion within-subject differences. Within-subject variation of eccentric knee extension was correlated (P<0.05) with chronologic age (r=0.41), estimated age at peak height velocity (r=–0.38), body size (r=0.41 to 0.47), and leg volume (r=0.39). Conclusions. Familiarization sessions may improve the reliability of concentric and eccentric knee isokinetic strength testing at 60º s–1 in adolescent basketball players. Age, maturity status, and training experience of young athletes should be considered when testing knee isokinetic strength at 60º s–1.

scholarly journals Age-Related Differences in Functional Hamstring/Quadriceps Ratio Following Soccer Exercise in Female Youth Players: An Injury Risk Factor

2018 ◽  
Vol 30 (3) ◽  
pp. 376-382 ◽  
Author(s):  
Mark De Ste Croix ◽  
Abigail Priestley ◽  
Rhodri Lloyd ◽  
Jon Oliver
Keyword(s):  
Knee Flexion ◽  
Injury Risk ◽  
Knee Extension ◽  
Peak Height ◽  
Height Velocity ◽  
Peak Height Velocity ◽  
Specific Exercise ◽  
Movement Velocity ◽  
Full Extension ◽  
Age Related

Purpose: Fatigue negatively alters dynamic knee control, and the functional hamstring/quadriceps ratio (H/QFUNC) plays an important role in stabilizing the joint. The aim of this study was to investigate the influence of soccer-specific exercise on H/QFUNC in under (U) 13-, U15-, and U17-year-old female soccer players. Methods: A total of 36 female players performed concentric and eccentric actions of the hamstrings at 60°, 120°, and 180°/s before and after an age group–specific field-based soccer protocol. H/QFUNC was determined in the first 30° of knee flexion. Results: Significant angle × velocity (P = .001) and time × angle (P = .033) interaction effects were found indicating a lower H/QFUNC with increased movement velocity at 0°–10° as opposed to greater knee flexion angles. Fatigue-related effects were only evident near full knee extension. Probabilistic inferences indicated that changes in H/QFUNC were generally unclear in U13s, likely detrimental in U15s, and very likely beneficial in U17s. Conclusions: Altered muscular control following soccer-specific exercise is age dependent with players’ 1-year post-peak height velocity at greatest risk of injury. Injury prevention and screening need to be age and maturation appropriate, should consider the effects of fatigue, and include movements near full extension.

scholarly journals The Study of Maturational Timing Effect in Elite Portuguese Adolescent Basketball Players: Anthropometric, Functional and Game Performance Implications

2021 ◽  
Vol 11 (21) ◽  
pp. 9894
Author(s):  
Isabel Fragoso ◽  
Sérgio Ramos ◽  
Júlia Teles ◽  
Anna Volossovitch ◽  
António Paulo Ferreira ◽  
...  
Keyword(s):  
Peak Height ◽  
Upper Body ◽  
Height Velocity ◽  
Peak Height Velocity ◽  
Basketball Players ◽  
Cross Sectional ◽  
Male Adolescents ◽  
Body Strength ◽  
Upper Body Strength ◽  
Game Performance

To estimate age at peak height velocity (APHV) in Portuguese male adolescents and; test the effect of maturational status in physical fitness attributes and individual game performance of U-14 basketball players. One mixed-longitudinal cohort with a sample of 439 Portuguese male adolescents and; one cross sectional sample of 172 Portuguese elite U-14 basketball players. The on-time group was defined within a 1-year band (more or less) from mean APHV. Preece-Baines model 1 was adopted to fit the mean stature curve. Independent samples t-tests and Kruskal-Wallis tests were performed and effect size (partial eta square) was calculated. The growth fitting revealed an APHV around 13.45 years for Portuguese male adolescents. Early maturing players exceeded significantly their peers in body size and composition, jump power and upper body strength. Early and on-time maturing players scored better in rebounds won per game (APHV = 13.81, 13.30 years), Performance Index Rating (PIR) and points scored per minute. Maturation influences morphology attributes and strength regardless of the APHV (13.81, 13.45, 13.30 years) used to obtain the cut-off points. It is recommended to use the new Portuguese mean APHV value to avoid extreme classifying bias groups.

scholarly journals Modeling developmental changes in strength and aerobic power in children

1998 ◽  
Vol 84 (3) ◽  
pp. 963-970 ◽  
Author(s):  
Alan M. Nevill ◽  
Roger L. Holder ◽  
Adam Baxter-Jones ◽  
Joan M. Round ◽  
David A. Jones
Keyword(s):  
Body Size ◽  
Multilevel Model ◽  
Aerobic Power ◽  
Peak Height ◽  
Height Velocity ◽  
Additional Contribution ◽  
Multilevel Regression ◽  
Peak Height Velocity ◽  
Polynomial Structure ◽  
Model Structures

The present study examined two contrasting multilevel model structures to describe the developmental (longitudinal) changes in strength and aerobic power in children: 1) an additive polynomial structure and 2) a multiplicative structure with allometric body size components. On the basis of the maximum log-likelihood criterion, the multiplicative “allometric” model was shown to be superior to the additive polynomial model when fitted to the data from two published longitudinal studies and to provide more plausible solutions within and beyond the range of observations.The multilevel regression analysis of study 1 confirmed that aerobic power develops approximately in proportion to body mass, m 1/3. The analyses from study 2 identified a significant increase in quadriceps and biceps strength, in proportion to body size, plus an additional contribution from age, centered at about peak height velocity (PHV). The positive “age” term for boys suggested that at PHV the boys were becoming stronger in the quadriceps and biceps in relation to their body size. In contrast, the girls’ age term was either negligible (quadriceps) or negative (biceps), indicating that at PHV the girls’ strength was developing in proportion to or, in the case of the biceps, was becoming weaker in relation to their body size.

scholarly journals Morphological and Fitness Attributes of Young Male Portuguese Basketball Players: Normative Values According to Chronological Age and Years From Peak Height Velocity

2021 ◽  
Vol 3 ◽  
Author(s):  
Sérgio Antunes Ramos ◽  
Luis Miguel Massuça ◽  
Anna Volossovitch ◽  
António Paulo Ferreira ◽  
Isabel Fragoso
Keyword(s):  
Body Mass ◽  
Handgrip Strength ◽  
Young Male ◽  
Peak Height ◽  
Height Velocity ◽  
Chronological Age ◽  
Normative Values ◽  
Peak Height Velocity ◽  
Basketball Players ◽  
Arm Span

The aims of the present study were: (i) to describe the structural and functional attributes of young male Portuguese basketball players aged 12–16 years and (ii) to generate normative data according to chronological age and years from peak height velocity. A total of 281 male Portuguese young basketball players between the ages of 12 and 16 years were assessed in this study. Chronological age, maturity parameters (maturity offset and predicted age at peak height velocity), morphological (body mass, height, and skinfolds and length), and fitness (sprint, change of direction ability, jump, and upper body strength) attributes were measured. Descriptive statistics were determined for the age and maturity status, and the 10th, 25th, 50th, 75th, and 90th percentiles were chosen as reference values. Descriptive and normative values of the players' morphological and fitness attributes, stratified by age and maturity status, are provided. The normative values of age at peak height velocity (category YAPHV = 0) showed that regional basketball players presented average values (50th percentile) of 169.8 cm for height, 173.3 cm for arm span, 55.6 kg for body mass, 3.34 s for the 20-m speed test, 10.31 s for the T-test, 4.75 m for the 2-kg medicine ball throw, 66.9 kg for the combined right and left handgrip strength, and 30.1 and 35.9 cm for jump height in the countermovement jump (CMJ) and CMJ with arm swing, respectively. In conclusion, these results may be helpful to quantify and control an athlete's performance over time and to adjust strength and conditioning programs to biological demands.

scholarly journals Repeated Sprint Ability in Youth Soccer Players: Independent and Combined Effects of Relative Age and Biological Maturity

2019 ◽  
Vol 67 (1) ◽  
pp. 209-221 ◽  
Author(s):  
João P. Duarte ◽  
Manuel J. Coelho-e-Silva ◽  
Daniela Costa ◽  
Diogo Martinho ◽  
Leonardo G. O. Luz ◽  
...  
Keyword(s):  
Body Size ◽  
Peak Height ◽  
Height Velocity ◽  
Combined Effects ◽  
Peak Height Velocity ◽  
Youth Soccer ◽  
Relative Age ◽  
Repeated Sprint Ability ◽  
Repeated Sprint ◽  
Sprint Ability

AbstractThe objective of the study was to examine the effects of the relative age effect (RAE) and predicted maturity status on body size and repeated sprint ability (RSA: 7 x 34.2 m / 25 s interval) in youth soccer. The sample was composed of 197 male players aged 13-14 years. Body mass, stature, and sitting height were measured, RSA was assessed in the field, and age at peak height velocity (APHV) was predicted. Factorial ANOVA tested the independent and combined effects of RAE given by birth quarters (BQs) and maturity status on dependent variables. Players born in the second birth quarter (BQ2) were significantly taller (F = 4.28, p < 0.01) than their peers born in BQ1 and BQ3. Additionally, players born in BQ2 performed better than players born in BQ4 in RSA total time and ideal time (F ranged between 4.81 and 4.90, p < 0.01), while players born in BQ1 exhibited a lower RSA fatigue index compared to those born in BQ4 (F = 2.90, p < 0.05). The interaction of the BQ and maturity status was a significant source of inter-individual variation for body size (F ranged between 64.92 and 105.57; p < 0.01) and RSA output (F ranged between 4.082 and 6.76; p < 0.05). In summary, being relatively older and, simultaneously, advanced in maturity status corresponds to a substantial advantage in characteristics that are related to soccer-specific fitness.

Maturational Development as a Key Aspect in Physiological Performance and National-Team Selection in Elite Male Basketball Players

2019 ◽  
Vol 14 (7) ◽  
pp. 902-910 ◽  
Author(s):  
Jorge Arede ◽  
António Paulo Ferreira ◽  
Oliver Gonzalo-Skok ◽  
Nuno Leite
Keyword(s):  
Aerobic Fitness ◽  
Characteristic Curve ◽  
Height Velocity ◽  
Physical Parameters ◽  
Peak Height Velocity ◽  
Training Experience ◽  
Basketball Players ◽  
National Team ◽  
Team Selection ◽  
Power Outputs

Purpose:To determine the discriminators as variables to select the under-16 national-team players and to examine the influence of biological age on physical/technical parameters among young basketball players.Methods:Thirty-four under-15 male basketball players performed several anthropometrical (height, wingspan, body mass, and fingers length) and physical (jumping, sprinting, throwing, flexibility, change-of-direction speed, and aerobic fitness) tests during the under-15 male national-team training camp. Maturity offset, lower-limb asymmetry index, and power outputs for jumping and sprinting were also computed. In addition, game performance was taken into consideration using game-related statistics (assists, turnovers, steals, rebounds, blocks, and points) of 5 games of during the previous regional tournament (April 2016). Cluster analysis was used to analyze the between-maturation status (prepubertal, pubertal, and postpubertal) differences in physical parameters.Results:The postpubertals showed a significantly better performance in power outputs (jumping and sprinting), throwing abilities, and blocks, whereas prepubertal performed significantly better in aerobic fitness and assists. Receiver-operating-characteristic curve confirmed maturational status (area under the curve [AUC] = 0.804;P < .05) and training experience (AUC = 0.789;P < .05) as the most important attributes in predicting under-16 national-team selection. Players with more than 5.5 years of training experience and less than 1.4 y to the age at peak height velocity were most likely to be selected.Conclusion:Maturational status seems to be a key variable that increases the probability of selection for the Portuguese under-16 national team.

scholarly journals Optimum Angle of Force Production Temporarily Changes Due to Growth in Male Adolescence

Children ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 20
Author(s):  
Junya Saeki ◽  
Satoshi Iizuka ◽  
Hiroaki Sekino ◽  
Ayahiro Suzuki ◽  
Toshihiro Maemichi ◽  
...  
Keyword(s):  
Force Production ◽  
Knee Extension ◽  
Peak Height ◽  
Height Velocity ◽  
Outcome Variable ◽  
P Value ◽  
Peak Height Velocity ◽  
Optimum Angle ◽  
The Difference ◽  
Polynomial Formula

The peak increase in lean mass in adolescents is delayed from peak height velocity (PHV), and muscle flexibility temporarily decreases as bones grow. If the decrease in muscle flexibility is caused by muscle elongation, the relationship between the exerted torque and the joint angle could change in adolescents. The purpose of this study was to investigate the change in the optimum angle of force production due to growth. Eighty-eight healthy boys were recruited for this study. Isokinetic knee extension muscle strength of the dominant leg was recorded. The outcome variable was the knee flexion angle when maximal knee extension torque was produced (optimum angle). The age at which PHV occurred was estimated from subjects’ height history. We calculated the difference between the age at measurement and the expected age of PHV (growth age). A regression analysis was performed with the optimal angle of force exertion as the dependent variable and the growth age as the independent variable. Then, a polynomial formula with the lowest p-value was obtained. A significant cubic regression was obtained between optimum angle and growth age. The results suggest that the optimum angle of force production temporarily changes in male adolescence.

scholarly journals Are Early or Late Maturers Likely to Be Fitter in the General Population?

2021 ◽  
Vol 18 (2) ◽  
pp. 497
Author(s):  
Alan M. Nevill ◽  
Yassine Negra ◽  
Tony D. Myers ◽  
Michael J. Duncan ◽  
Helmi Chaabene ◽  
...  
Keyword(s):  
Body Size ◽  
Physical Fitness ◽  
Handgrip Strength ◽  
Peak Height ◽  
Height Velocity ◽  
Chronological Age ◽  
Peak Height Velocity ◽  
Late Maturer ◽  
Fitness Tests ◽  
Shape Ratio

The present study aims to identify the optimal body-size/shape and maturity characteristics associated with superior fitness test performances having controlled for body-size, sex, and chronological-age differences. The sample consisted of 597 Tunisian children (396 boys and 201 girls) aged 8 to 15 years. Three sprint speeds recorded at 10, 20 and 30 m; two vertical and two horizontal jump tests; a change-of-direction and a handgrip-strength tests, were assessed during physical-education classes. Allometric modelling was used to identify the benefit of being an early or late maturer. Findings showed that being tall and light is the ideal shape to be successful at most physical fitness tests, but the height-to-weight “shape” ratio seems to be test-dependent. Having controlled for body-size/shape, sex, and chronological age, the model identified maturity-offset as an additional predictor. Boys who go earlier/younger through peak-height-velocity (PHV) outperform those who go at a later/older age. However, most of the girls’ physical-fitness tests peaked at the age at PHV and decline thereafter. Girls whose age at PHV was near the middle of the age range would appear to have an advantage compared to early or late maturers. These findings have important implications for talent scouts and coaches wishing to recruit children into their sports/athletic clubs.

scholarly journals Influence of age and maturation on perceived collective efficacy in youth basketball players

2019 ◽  
Vol 19 (1) ◽  
pp. 275-282
Author(s):  
William N. Salles ◽  
André L. A. Soares ◽  
Carine Collet ◽  
Fabrício J. Milan ◽  
Carlos E. Palheta ◽  
...  
Keyword(s):  
Collective Efficacy ◽  
Functional Performance ◽  
Peak Height ◽  
Height Velocity ◽  
Chronological Age ◽  
Peak Height Velocity ◽  
Basketball Players ◽  
Holistic Understanding ◽  
Age Variation ◽  
Performance Development

Growth and maturation impact the development of young athletes’ physique and function. It is likely that psychological and behavioral characteristics will also be impacted by maturity status. Perceived collective efficacy (CE) is a potential mediator of sports performance and may be influenciated by maturity status. Therefore, this study examined the perceived CE variation between young basketball players accounting for the influence of chronological age and biological maturity status. The sample included 57 adolescent basketball players aged 9.5 to 15.5 years. Chronological age, estimated age at peak height velocity (PHV) and CE through the Portuguese version of the Collective Efficacy Questionnaire for Sports were considered. Bayesian multilevel modeling was used to examine athletes’ perceived CE dimensions variation by maturity status and age. Overall, the adolescent basketball players’ perceived CE scores were high for all dimensions: ability (8.77±1.15); effort (9.20±1.03); persistence (8.87±1.18); preparation (8.96±1.08); unity (8.88±1.22). The variability estimates were very large, suggesting that the influence of maturity status on variation may be residual. There was no substantial relation between chronological age and the variation scores, although the results suggest that perceived variation was independent of chronological age variation and between players variation in maturity status. Further study examining the relations of growth, functional performance development, and perceived CE would be relevant for the holistic understanding of young basketball players’ development. Growth and maturation impact the development of young athletes’ physique and function. It is likely that psychological and behavioral characteristics will also be impacted by maturity status. Perceived collective efficacy (CE) is a potential mediator of sports performance and may be influenciated by maturity status. Therefore, this study examined the perceived CE variation between young basketball players accounting for the influence of chronological age and biological maturity status. The sample included 57 adolescent basketball players aged 9.5 to 15.5 years. Chronological age, estimated age at peak height velocity (PHV) and CE through the Portuguese version of the Collective Efficacy Questionnaire for Sports were considered. Bayesian multilevel modeling was used to examine athletes’ perceived CE dimensions variation by maturity status and age. Overall, the adolescent basketball players’ perceived CE scores were high for all dimensions: ability (8.77±1.15); effort (9.20±1.03); persistence (8.87±1.18); preparation (8.96±1.08); unity (8.88±1.22). The variability estimates were very large, suggesting that the influence of maturity status on variation may be residual. There was no substantial relation between chronological age and the variation scores, although the results suggest that perceived variation was independent of chronological age variation and between players variation in maturity status. Further study examining the relations of growth, functional performance development, and perceived CE would be relevant for the holistic understanding of young basketball players’ development.

scholarly journals Breakfast: A Crucial Meal for Adolescents’ Cognitive Performance According to Their Nutritional Status. The Cogni-Action Project

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1320
Author(s):  
Humberto Peña-Jorquera ◽  
Valentina Campos-Núñez ◽  
Kabir P. Sadarangani ◽  
Gerson Ferrari ◽  
Carlos Jorquera-Aguilera ◽  
...  
Keyword(s):  
Nutritional Status ◽  
Cognitive Performance ◽  
Cognitive Demand ◽  
Positive Association ◽  
Peak Height ◽  
The Body ◽  
Height Velocity ◽  
Peak Height Velocity ◽  
High Quality ◽  
Action Project

This study aimed to determine whether pupils who have breakfast just before a cognitive demand, do not regularly skip breakfast, and consume a high-quality breakfast present higher cognitive performance than those who do not; furthermore, to establish differences according to their nutritional status. In this study, 1181 Chilean adolescents aged 10–14 years participated. A global cognitive score was computed through eight tasks, and the body mass index z-score (BMIz) was calculated using a growth reference for school-aged adolescents. The characteristics of breakfast were self-reported. Analyses of covariance were performed to determine differences in cognitive performance according to BMIz groups adjusted to sex, peak height velocity, physical fitness global score, and their schools. A positive association was found in adolescents’ cognitive performance when they had breakfast just before cognitive tasks, did not regularly skip breakfast, presented at least two breakfast quality components, and included dairy products. No significant differences were found between breakfast components, including cereal/bread and fruits/fruit juice. Finally, pupils who were overweight/obese who declared that they skipped breakfast regularly presented a lower cognitive performance than their normal-BMIz peers. These findings suggest that adolescents who have breakfast just prior to a cognitive demand and regularly have a high quality breakfast have better cognitive performance than those who do not. Educative nutritional strategies should be prioritized, especially in “breakfast skippers” adolescents living with overweight/obesity.

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