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 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 Injury Risk and Injury Burden Are Related to Age Group and Peak Height Velocity Among Talented Male Youth Soccer Players

2018 ◽  
Vol 6 (12) ◽  
pp. 232596711881104 ◽  
Author(s):  
Hans Jan Bult ◽  
Maarten Barendrecht ◽  
Igor Joeri Ramon Tak
Keyword(s):  
Injury Risk ◽  
Age Groups ◽  
Peak Height ◽  
Soccer Players ◽  
Height Velocity ◽  
Incidence Density ◽  
Chronological Age ◽  
Peak Height Velocity ◽  
The Mean ◽  
Injury Burden

Background: The relationship between injury risk (IR) in age groups and periods around peak height velocity (PHV) remains unclear. PHV is defined as the moment of the largest increase in body height. Purpose: To investigate injury risk and injury burden as functions of growth velocity (periods around PHV) and chronological age groupings (under 12 years [U12] to U19) in talented youth male soccer players. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 170 players from the youth academy of a Dutch soccer club (highest professional league: Eredivisie) were observed for 1 to 3 seasons. Injuries, exposure, PHV age, and chronological age were registered. The injury incidence density (IID) and injury burden per 1000 hours of soccer participation, with 95% CIs, were calculated for 5 PHV periods and 7 age groups. These were compared with the overall cohort results using incidence ratios (IRs) and burden ratios (BRs) with 95% CIs. Results: The mean age at PHV was 14.4 ± 0.65 years (range, 12.8-16.5 years). The mean IID for the total cohort was 8.34 injuries per 1000 hours (95% CI, 7.71-9.02). Compared with the overall mean, a significantly higher IID was found for PHV period 4+5 (IR, 1.31 [95% CI, 1.00-1.71]; P = .049) and for the U15 group (IR, 1.49 [95% CI, 1.24-1.79]; P < .001). The overall injury burden was 58.37 injury days per 1000 hours (95% CI, 56.66-60.13). In PHV period 4+5, the injury burden was significantly higher (BR, 1.53 [95% CI, 1.39-1.68]; P < .001) when compared with the overall mean. Also, compared with the overall mean, the injury burden was higher in the U16 (BR, 1.48 [95% CI, 1.39-1.58]; P < .001), U15 (BR, 1.28 [95% CI, 1.19-1.38]; P < .001), and U17 groups (BR, 1.21 [95% CI, 1.13-1.31]; P < .001). Conclusion: Talented young soccer players were more prone to injuries during the 6 months after PHV (31% above overall mean) as well as in the U15 group (49% above overall mean). Based on the higher injury burden in the U16 (48%), U15 (28%), and U17 (21%) groups, we suggest that research on injury risk factors and preventive measures should primarily target these age groups. Additional interventions based on PHV may be of limited value from a screening perspective. Further research is needed on the interaction between age groups and PHV periods.

scholarly journals Age-related differences in linear sprint in adolescent female soccer players

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Elena Mainer-Pardos ◽  
Oliver Gonzalo-Skok ◽  
Hadi Nobari ◽  
Demetrio Lozano ◽  
Jorge Pérez-Gómez
Keyword(s):  
Body Mass ◽  
Peak Height ◽  
Sprint Performance ◽  
Soccer Players ◽  
Height Velocity ◽  
Adolescent Female ◽  
Peak Height Velocity ◽  
Running Speed ◽  
Biological Maturation ◽  
Age Related

Abstract Background Several studies have observed the contribution of chronological age, biological maturation, and anthropometric characteristics to sprinting performance in young soccer players. Nevertheless, there are no studies that have analysed the contribution of these characteristics to running speed qualities in adolescent female soccer players. Objective This study investigated age-related differences in sprint performance in adolescent female soccer players. Also, it examined the possible influence of anthropometry [body mass and body mass index (BMI)] and biological maturation [age at peak height velocity (APHV)] in sprint performance. Methods Eighty adolescent female soccer players [under (U) 14, n = 20; U16, n = 37; U18, n = 23] participated in this study. Players were tested for 40 m sprint (each 10 m split times). Results Posthoc analysis revealed better performance in all split sprint times of older soccer players (U18 and U16) compared with younger category (F: 3.380 to 6.169; p < 0.05; ES: 0.64 to 1.33). On the contrary in all split sprint times, there were no significant changes between U16 and U18 (p < 0.05; ES: 0.03 to 0.17). ANCOVA revealed differences in all parameters between groups, controlled for APHV (p < 0.05). In contrast, all between-group differences disappeared after body mass and BMI adjustment (p > 0.05). Finally, the results indicate that BMI and body mass were significantly correlated with 40 m sprint (p < 0.05; r: -0.31) and 20 m flying (p < 0.01; r: 0.38), respectively. Conclusion In the present players’ sample, body mass and BMI had a significant impact on running speed qualities.

scholarly journals Sports injuries aligned to predicted mature height in highly trained Middle-Eastern youth athletes: a cohort study

BMJ Open ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. e023284 ◽  
Author(s):  
Abdallah Rejeb ◽  
Amanda Johnson ◽  
Abdulaziz Farooq ◽  
Ruth Verrelst ◽  
Samuel Pullinger ◽  
...  
Keyword(s):  
Cohort Study ◽  
Injury Risk ◽  
Middle Eastern ◽  
Peak Height ◽  
Height Velocity ◽  
Injury Incidence ◽  
Peak Height Velocity ◽  
Early Maturity ◽  
Youth Athletes ◽  
Individual Sports

ObjectivesTo investigate the association of maturity status with injury incidence in Middle-Eastern youth athletes.DesignProspective cohort study.SettingFour consecutive seasons (2010–2014), Aspire Academy, Qatar.ParticipantsMale athletes (age range: 11–18 years) representing four disciplines enrolled and grouped into two categories: individual sports and racquet sports.Outcome measuresInjury data collected over four seasons. Athletes’ anthropometric characteristics assessed to calculate age at peak height velocity. Predicted mature heights (PMHs) collected and categorised into four quartiles. Athletes had wrist and hand radiographs for assessment of skeletal age (SA). Early and late maturers with an SA of >1 year older or younger than their chronological age (CA).ResultsFor the sample (n=67) across all groups, 43 (64%) athletes had one or more injuries: total of 212 injuries, 4.9 injuries per athlete across study. Survival analysis of maturity status using SA found early maturing athletes had two-fold greater injury risk compared with late maturers (HR 2.04, 95% CI 1.15 to 3.61, p=0.015). PMH associated with injury risk (HR 1.05, 95% CI 1.01 to 1.08, p=0.006).Athletes in fourth quartile (≥184 cm) had up to two-fold injury risk (HR 2.41, 95% CI 1.42 to 4.08, p=0.001). Racquet and individual sports involved similar injury risk (HR 1.14, 95% CI 0.86 to 1.52, p=0.37).ConclusionSA early maturity and PMH gradient were significant predictors of injury in youths.

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 Physical Activity–Related Injury Profile in Children and Adolescents According to Their Age, Maturation, and Level of Sports Participation

2017 ◽  
Vol 9 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Lara Costa e Silva ◽  
Maria Isabel Fragoso ◽  
Júlia Teles
Keyword(s):  
Physical Activity ◽  
Injury Risk ◽  
Injury Rate ◽  
Sports Participation ◽  
Bone Age ◽  
Peak Height ◽  
Height Velocity ◽  
Peak Height Velocity ◽  
Biological Maturation ◽  
Early Maturing

Background: Physical activity (PA) is beneficial, enhancing healthy development. However, one-third of school-age children practicing sports regularly suffer from an injury. These injuries are associated with sex, chronological age, and PA level. Purpose: To identify the importance of age, PA level, and maturity as predictors of injury in Portuguese youth. Study Design: Descriptive epidemiological study. Level of Evidence: Level 3. Methods: Information about injury and PA level was assessed via 2 questionnaires (LESADO RAPIL II) from 647 subjects aged 10 to 17 years. Maturity offset according to Mirwald (time before or after peak height velocity) and Tanner-Whitehouse III bone age estimates were used to evaluate maturation. Binary logistic regression and gamma regression were used to determine significant predictors of injury and injury rate. Results: Injury occurrence was higher for both sexes in recreational, school, and federated athletes (athletes engaged in sports that are regulated by their respective federations, with formal competition). These injuries also increased with age in boys and in the higher maturity offset group in girls. Injury rate was higher for both sexes in the no sports participation group. Early-maturing girls, with higher bone age and lower maturity offset, showed higher injury rate. Conclusion: Injuries in Portuguese youth were related to PA level, age, and biological maturation. Recreational, school, and federated athletes had more injury ocurrences while subjects with no sports participation had higher injury risk. Older subjects had more injuries. Early-maturing girls that had just passed peak height velocity may be particularly vulnerable to risk of sports injury because of the growing process. Clinical Relevance: Increased knowledge about injury with specific PA exposure data is important to an overall risk management strategy. This study has deepened the association between injury and biological maturation variables.

scholarly journals The Influence of Age and Maturation on Trajectories of Stretch-Shortening Cycle Capability in Male Youth Team Sports

2020 ◽  
pp. 1-7
Author(s):  
Mark De Ste Croix ◽  
Michal Lehnert ◽  
Eliska Maixnerova ◽  
Francisco Ayala ◽  
Rudolf Psotta
Keyword(s):  
Injury Risk ◽  
Longitudinal Design ◽  
Team Sports ◽  
Peak Height ◽  
Height Velocity ◽  
Peak Height Velocity ◽  
Leg Stiffness ◽  
Stretch Shortening Cycle ◽  
Bayesian Factor ◽  
Over Time

Purpose: To examine the influence of growth and maturation in the trajectory of stretch-shortening cycle capability. Method: Using a mixed-longitudinal design, absolute and relative leg stiffness and reactive strength index (RSI) were measured 3 times over a 3-year period in 44 youth team-sport players. Maturation was determined as maturity offset and included within the Bayesian inference analysis as a covariate alongside chronological age. Results: Irrespective of age and maturation, there was no change in absolute leg stiffness, however relative leg stiffness decreased over time. Maturation and age reduced this decline, but the decline remained significant (Bayesian factor [10] = 5097, model averaged R2 = .61). The RSI increased over time and more so in older more mature youth players (Bayesian factor [10] = 9.29e8, model averaged R2 = .657). Conclusion: In youth players who are at/post peak height velocity, relative leg stiffness appears to decline, which could have an impact on both performance and injury risk. However, RSI increases during this period, and these data reinforce that leg stiffness and RSI reflect different components of stretch-shortening cycle capability. Practitioners should consider these differences when planning training to maximize stretch-shortening cycle capability during growth and maturation in athletes on the developmental performance pathway.

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.

scholarly journals Growth in achondroplasia, from birth to adulthood, analysed by the JPA-2 model

2020 ◽  
Vol 33 (12) ◽  
pp. 1589-1595
Author(s):  
Mariana del Pino ◽  
Virginia Fano ◽  
Paula Adamo
Keyword(s):  
General Population ◽  
Growth Curve ◽  
Growth Velocity ◽  
Adult Height ◽  
Growth Curves ◽  
Peak Height ◽  
Height Growth ◽  
Individual Growth ◽  
Height Velocity ◽  
Peak Height Velocity

AbstractObjectivesIn general population, there are three phases in the human growth curve: infancy, childhood and puberty, with different main factors involved in their regulation and mathematical models to fit them. Achondroplasia children experience a fast decreasing growth during infancy and an “adolescent growth spurt”; however, there are no longitudinal studies that cover the analysis of the whole post-natal growth. Here we analyse the whole growth curve from infancy to adulthood applying the JPA-2 mathematical model.MethodsTwenty-seven patients, 17 girls and 10 boys with achondroplasia, who reached adult size, were included. Height growth data was collected from birth until adulthood. Individual growth curves were estimated by fitting the JPA-2 model to each individual’s height for age data.ResultsHeight growth velocity curves show that after a period of fast decreasing growth velocity since birth, with a mean of 9.7 cm/year at 1 year old, the growth velocity is stable in late preschool years, with a mean of 4.2 cm/year. In boys, age and peak height velocity in puberty were 13.75 years and 5.08 cm/year and reach a mean adult height of 130.52 cm. In girls, the age and peak height velocity in puberty were 11.1 years and 4.32 cm/year and reach a mean adult height of 119.2 cm.ConclusionsThe study of individual growth curves in achondroplasia children by the JPA-2 model shows the three periods, infancy, childhood and puberty, with a similar shape but lesser in magnitude than general population.

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