Predicting the timing of the peak of the pubertal growth spurt in elite youth soccer players: evaluation of methods.

Background: Three commonly used non-invasive protocols are implemented to estimate the timing at which PHV most likely occurs. Accurate estimation of circumpubertal years can aid in managing training load of adolescent athletes.Aim: Three protocols were compared against observed age at PHV: an estimate of 13.8 ± 1.0 years - generic age at PHV (from longitudinal measures); an estimate based on the maturity offset equation, predicted age at PHV ±1.0 year; a window of PHV based on 85 - 96% of predicted adult height at time of observation.Subjects and methods: A final sample of 23 (from 28) adolescent participants who were selected from the academy of an English Premier League club. Anthropometric measures were collected across five playing seasons; age at PHV was estimated with Super-Imposition by Translation and Rotation (SITAR). The three protocols were compared based on measures at 13.0 years.Results and Conclusions: An age window based on predicted maturity offset did not improve estimation of PHV compared to generic age method; however, the percentage of predicted adult height window showed improvement in performance shown by the following results. Predicted age at PHV correctly assigned 15 participants (65%) as experiencing PHV, while the percentage height correctly assigned 17 participants (74%). Generic age and predicted age at PHV correctly predicted observed age at PHV for 14 participants (61%), percentage of adult height window correctly predicted 22 participants (96%)

Fitness and Adiposity Are Independently Associated with Cardiometabolic Risk in Youth

Purpose. The purpose of the study was to examine the independent associations of adiposity and cardiorespiratory fitness with clustered cardiometabolic risk. Methods. A cross-sectional sample of 192 adolescents (118 boys), aged 14–16 years, was recruited from a South Lanarkshire school in the West of Scotland. Anthropometry and blood pressure were measured, and blood samples were taken. The 20 m multistage fitness test was the indicator of cardiorespiratory fitness (CRF). A clustered cardiometabolic risk score was constructed from HDL-C (inverted), LDL-C, HOMA, systolic blood pressure, and triglycerides. Interleukin-6, C-reactive protein, and adiponectin were also measured and examined relative to the clustered cardiometabolic risk score, CRF, and adiposity. Results. Although significant, partial correlations between BMI and waist circumference (WC) and both CRF and adiponectin were negative and weak to moderate, while correlations between the BMI and WC and CRP were positive but weak to moderate. Weak to moderate negative associations were also evident for adiponectin with CRP, IL-6, and clustered cardiometabolic risk. WC was positively associated while CRF was negatively associated with clustered cardiometabolic risk. With the additional adjustment for either WC or CRF, the independent associations with cardiometabolic risk persisted. Conclusion. WC and CRF are independently associated with clustered cardiometabolic risk in Scottish adolescent

A prospective analysis of the injury incidence of young male professional football players on artificial turf

Background: The effects of synthetic surfaces on the risk of injuries is still debated in literature and the majority of published data seems to be contradictory. For such reasons the understanding of injury incidence on such surfaces, especially in youth sport, is fundamental for injury prevention. Objectives: The aim of this study was to prospectively report the epidemiology of injuries in young football players, playing on artificial turfs, during a one sports season. Patients and Methods: 80 young male football players (age 16.1 ± 3.7 years; height 174 ± 6.6 cm; weight 64.2 ± 6.3 kg) were enrolled in a prospective cohort study. The participants were then divided in two groups; the first included players age ranging from 17 to 19 (OP) whereas the second included players age ranging from 13 to 16 (YP). Injury incidence was recorded prospectively, according to the consensus statement for soccer. Results: A total of 107 injuries (35 from the OP and 72 from the YP) were recorded during an exposure time of 83.760 hours (incidence 1.28/1000 per player hours); 22 during matches (incidence 2.84/1000 per player hours, 20.5%) and 85 during training (incidence 1.15/1000 per player hours, 79.5%). Thigh and groin were the most common injury locations (33.6% and 21.5%, respectively) while muscle injuries such as contractures and strains were the most common injury typologies (68.23%). No statistical differences between groups were displayed, except for the rate of severe injuries during matches, with the OP displaying slightly higher rates compared to the YP. Severe injuries accounted for 10.28% of the total injuries reported. The average time lost due to injuries was 14 days. Re-injuries accounted for 4.67% of all injuries sustained during the season. Conclusions: In professional youth soccer injury rates are reasonably low. Muscle injuries are the most common type of injuries while groin and thigh the most common locations. Artificial turf pitches don’t seem to contribute to injury incidence in young football players

Establishing consensus of position-specific predictors for elite youth soccer in England

Purpose: To construct a valid and reliable methodology for the development of position-specific predictors deemed appropriate for talent identification purposes within elite youth soccer in England. Method: N = 10 panel experts participated in a three-step modified e-Delphi poll to generate consensus on a series of generic youth player attributes. A follow-up electronic survey completed by coaches, scouts and recruitment staff (n = 99) ranked these attributes to specific player-positions. Results: A final list of 44 player attributes found consensus using the three-step modified e-Delphi poll. Findings indicated that player-positional attributes considered most important in the youth phase are more psychological and technical than physiological or anthropometric. Despite ‘hidden’ attributes (e.g., coachability, flair, versatility, and vision) finding consensus on the e-Delphi poll, there was no evidence to support these traits when associated with a specific playing position. Conclusion: For those practitioners responsible for talent recruitment, our findings may provide greater understanding of the multiple attributes required for some playing positions. However, further ecological research is required to assess the veracity of our claims

Bio-banding in academy football: Player’s perceptions of a maturity matched tournament

Background: Individual differences in biological maturation impact player selection and development in youth football. Aim: To evaluate players perceptions of competing in a football tournament where they were matched by maturity rather than chronological age. Subjects: Participants included male junior footballers from three professional academies (n = 115). Methods: The study employed multiple methods of analysis, including one sample mean t-tests, equivalence tests, ANOVAs, and thematic analysis of qualitative data derived from open-ended questions. Results and conclusions: Player’s perceived the bio-banding format as providing two main benefits. Early maturing players perceived greater physical and technical challenge, and in turn new opportunities and challenges. Late maturing players perceived less physical and technical challenge, yet greater opportunity to demonstrate technical and tactical abilities. The players reported that they enjoyed and understood the purpose of the bio-banded format, and perceived less risk for injury. Players in all three maturity groups reported more opportunity to engage in leadership behaviours, influence game-play, and express themselves on the ball in the bio-banded format. Bio-banding may facilitate development for both early and late maturing academy players by presenting new learning environments and challenges

Towards Growing Robots: A Piecewise Morphology-Controller Co-adaptation Strategy for Legged Locomotion

Control of robots has largely been based on the assumption of a fixed morphology. Accordingly, robot designs have been stationary in time, except for the case of modular robots. Any drastic change in morphology, hence, requires a remodelling of the controller. This work takes inspiration from developmental robotics to present a piecewise morphology-controller growth/adaptation strategy that facilitates fast and reliable control adaptation to growing robots. We demonstrate our methodology on a simple 3 degree of freedom walking robot with adjustable foot lengths and with varying inertial conditions. Our results show not only the effectiveness and reliability of the piecewise morphology controller co-adaptation (PMCCA) strategy, but also highlight the need for morphological adaptation as a robot design strategy

Psychosocial correlates of physical activity in school children aged 8-10 years

Background: Understanding correlates of physical activity (PA) among children in different populations may contribute to fostering active lifestyles. This study considered gender differences in relationships between biologic (body mass index, BMI), demographic (socioeconomic sport status, SES) and psychosocial correlates of PA and level of PA in Portuguese primary school children. Methods: 683 children, aged 8–10 years, from 20 different elementary schools in northern Portugal were surveyed. Weight status was classified using International Obesity Task Force (IOTF) criteria for the BMI. Family SES was estimated from school records. PA level and psychosocial correlates (attraction to PA, perceived physical competence and parental socialization) were obtained with interview and standardized questionnaires, respectively. Sex-specific hierarchical multiple regression analyses (SPSS 18.0) were conducted and included two blocks of predictor variables (biologic and demographic, and psychosocial). Results: Level of PA was significantly higher in boys than girls. Enjoyment of participation in vigorous PA was positively associated with level of PA. Perceived acceptance by peers in games and sports and parental encouragement were positively and significantly related to PA in girls. Perceived physical competence was positively and significantly related to PA in boys. Weight status and SES were not associated with PA. Conclusions: Boys and girls differed in perceived attractiveness of PA and perceived physical competence, both of which influenced level of PA. Differences in perceptions may be important aspects of motivation for PA in school children

Metabolic risk factors, physical activity and physical fitness in azorean adolescents: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>The prevalence of metabolic syndrome has increased over the last few decades in adolescents and has become an important health challenge worldwide. This study analyzed the relationships between metabolic risk factors (MRF) and physical activity (PA) and physical fitness (PF) in a sample of Azorean adolescents.</p> <p>Methods</p> <p>A cross-sectional school-based study was conducted on 417 adolescents (243 girls) aged 15-18 from the Azorean Islands, Portugal. Height, weight, waist circumference, fasting glucose, HDL-cholesterol, triglycerides, and blood pressure were measured. A sum of MRF was computed, and adolescents were classified into three groups: no MRF, one MRF and two or more MRF. PA was assessed by a sealed pedometer. PF was assessed using five tests from the Fitnessgram Test Battery. Dietary intake was obtained using a semi-quantitative food frequency questionnaire.</p> <p>Results</p> <p>Mean daily steps for girls and boys were 7427 ± 2725 and 7916 ± 3936, respectively. Fifty-nine percent of the adolescents showed at least one MRF and 57.6% were under the healthy zone in the 20 m Shuttle Run Test. Ordinal logistic regression analysis showed that after adjusting for sex, body mass index, socio-economic status and adherence to a Mediterranean diet, adolescents who were in the highest quartile of the pedometer step/counts (≥9423 steps/day) and those who achieved the healthy zone in five tests were less likely to have one or more MRF (OR = 0.56;95%CI:0.33-0.95; OR = 0.55;95%CI:0.31-0.98, respectively).</p> <p>Conclusions</p> <p>Daily step counts and PF levels were negatively associated with having one or more MRF among Azorean adolescents. Our findings emphasize the importance of promoting and increasing regular PA and PF to reduce the public health burden of chronic diseases associated with a sedentary lifestyle.</p