U18 Groups Research Articles

Examining soccer skill performance using a dual task paradigm

The purpose of this study was to evaluate the reliability and validity of a holistic test (Soccer Skills and Cognitive Aptitude Test [SoSCAT]) that assesses soccer skills and performance in a dual-task (DT) context. A total of 73 male soccer players aged 12–18 years joined in this study. They were playing in three official Spanish regional leagues, and were divided according to their age into under 14 (U14, n = 25), under 16 (U16, n = 26), and under 18 (U18, n = 22). Additionally, players were categorized dichotomously into high-talented (n = 20) and lower-talented (n = 53) groups. Several soccer-skill and cognitive tests were evaluated. Regarding absolute reliability, the standard error of measurement (SEM) was 2.27 (5.30%) and the minimal detectable change (MDC) was 4.17 (9.75%). In relative reliability, the intra-class correlation coefficient was 0.908 (95% confidence interval [CI] = 0.826–0.951, p < 0.001). By category, the U18 group showed a higher performance in SoSCAT (p < 0.001) than U16 and U14. In addition, the DT cost (DTC) and ΔTime were the lowest in the U18 group (p = 0.041). Moreover, the high-talent group showed the best performance in SoSCAT (p = 0.001), DTC (p < 0.001), and in ΔTime (p < 0.001). To sum, the SoSCAT is a reliable tool for use under the DT context and it discriminates between levels of players and determines several variables that are relevant to soccer performance and that could help to early identify soccer talent.

Sex Differences Exist in the Relationship Between Vertical Jump Performance Biomechanical Parameters and Hamstring/Quadriceps Ratio in Adolescent U18 Track and Field Athletes.

Isokinetic metrics are suggested to be related to vertical jump performance, but little is known about the possible sex differences in this relationship in adolescent track and field athletes. The aim of the study was to examine the possible sex differences in the strength of the relationship between the kinetic parameters of the vertical squat jump with arms akimbo, the countermovement jump with arms akimbo, and the countermovement jump with free arm swing with the isokinetic parameters of the knee extensor and flexor muscles (angular velocities: 60°/s and 300°/s). In total, 35 (males: 21, females: 14) U18 track and field athletes were examined. The results revealed that the Men U18 group had higher vertical jump performance, higher values in the kinetic parameters of the vertical jump tests, higher knee extensor torque, and higher knee flexor torque in the non-dominant leg compared to the Women U18 group. Significant (p < 0.05) sex differences were observed in the relationship between the isokinetic parameters and the vertical jump performance metrics, as the Women U18 athletes relied more on the knee flexor torque than Men U18 athletes, and demonstrated a stronger negative relationship between selected isokinetic metrics and the pre-stretch gain in the vertical jump tests. In conclusion, it is recommended that young female track and field athletes minimize interlimb asymmetry and improve the convention ratio in their non-dominant leg to optimize vertical jump performance.

Differences in anthropometric and vertical jump force-time characteristics between U16 and U18 female basketball players.

Considering the importance of body composition and lower-body strength and power for basketball players' on-court performance, as well as a lack of sports science research focused on female athletes, the purpose of the present investigation was to record the anthropometric and countermovement vertical jump (CMJ) characteristics of top-tier U16 and U18 female basketball players and examine between-group differences in the aforementioned tests. Thirty-two athletes who were a part of the national basketball academy volunteered to participate in the present investigation. Following the body composition assessment conducted via a segmental multifrequency bioimpedance analyzer, athletes performed three CMJs while standing on a force plate system sampling at 1000 Hz. Independent t-test and Mann-Whitney U-test were used to examine between-group differences. The findings reveal significant differences in body composition and lower-body neuromuscular performance characteristics between female basketball players ages 16 and 18. Although no differences were observed in muscle and body fat percentages, the U18 group had significantly greater height, overall body mass (both muscle and fat mass), as well as greater segmental fat-free mass (trunk, both legs and arms), intracellular and extracellular water, and body mass index when compared to their U16 counterparts. On the other hand, the U18 group demonstrated longer eccentric, concentric, and braking phase duration, as well as overall contraction time when compared to the U16 players. In addition, the U18 athletes exhibited higher eccentric mean force and power, concentric impulse, peak power, and mean and peak force.

Head impact events in youth football in India and Australia, compared to FIFA Men's World Cup matches

This observational study compared incidence and characteristics of head impact events in matches in male youth under-18 football within Australia and India, to the Men's FIFA World Cup™ (FWC). Ten match videos from Australia, India and the 2018 FWC (total n ​= ​30) were coded for head impact events (purposeful headers and unintentional head impacts), match result as well as incidence rates (IR) per 1000 match-hours for heading performance characteristics. One-Way ANOVAs were conducted to assess statistical significance of heading IR and other characteristics. Purposeful headers (n ​= ​2734) were the most common head impact event (97%) with significantly more headers being completed by players from India (IR:3239) compared to Australia (IR: 2096) and FWC (IR: 2509). Most headers were completed during free play, via contact with the players forehead. Heading duels were more common in FWC matches (32%), than those in Australia (23%) or India (19%) (p ​< ​0.001). More headers occurred in the centre of the pitch (range 36–48%), with centre-backs completing the most headers across all groups (range 30–33%). Winning teams in India performed more headers from set-pieces than losing teams (p ​< ​0.001). In FWC matches, winning teams performed more headers in the defensive third compared to losing teams (p ​= ​0.02). Despite similar heading characteristics across both U18 groups and the FWC, players in India recorded higher heading incidence, suggesting that heading guidelines would benefit from being country and age specific.

Eccentric hamstring strength in young athletes is best documented when normalised to body mass: A cross-sectional study with normative data of 590 athletes from different age categories.

Despite its widespread use in adults, the Nordic hamstring exercise remains underexplored in athletic youth populations. Further, given the dynamic nature of growth and maturation, comparisons with elite adult populations may be inaccurate. Here we describe absolute and body mass-normalised eccentric hamstring normative values for football, athletics and multi-sport youth populations. 676 routine standardised tests were conducted, including 244 U12-U18 student-athletes (football, athletics, multi-sport) and 346 Qatar Stars League (QSL) football players using the NordBord. The average maximum values for the left and right leg from 3 repetitions were recorded. Significant increases in absolute strength were seen across chronological (e.g., 150 N ± 15 for U12 to 330 N ± 40 for U18) and skeletal (142.9 N ± 13.9 for skeletal age of 12 compared to 336.2 N ± 71.2 for skeletal age of 18) age groups. The differences in values normalised to body mass were smaller at 3.6 N/kg ± 0.25 for the U-13 group, but similar for the U14 to U18 groups (4.5 N/kg ± 0.16, 4.6 N/kg ± 0.11, 4.6 N/kg ± 0.27, 4.7 N/kg ± 0.14, 4.5 N/kg ± 0.18). Students displayed lower absolute strength than the professional football players (272.1 N compared to 297.3 N, p < 0.0001) but higher relative strength (4.7 N/kg compared to 4.2 N/kg, p < 0.0001). Comparing Nordic hamstring strength values between athletes, and between skeletal and chronological age groups can be done when values are normalised to the athlete's body mass. For the U14s and onwards age categories, body mass normalised values are comparable to professional football players.

Perception of Affordances in Soccer: Kicking for Power Versus Kicking for Precision

ABSTRACT Purpose: We investigated youth soccer players’ perception of affordances for different types of kicks. Method: In the Power task, players judged the maximum distance they could kick the ball. In the Precision task, players judged how close to a designated target line they could kick the ball. Following judgments, players performed each task. Both judgments and performance were assessed immediately before and immediately after players competed in a regulation soccer match, thereby permitting us to assess possible effects of long-term experience on perceptual sensitivity to short-term changes in ability. We compared players from two league groups: U16 (mean age = 15.45 years, SD = 0.52 years) versus U18 (mean age = 17.55 years, SD = 0.52 years). Results: As expected, for the Power task actual kicking ability was greater for the U18 group (p < .05). In statistically significant interactions, we found that judgments of Power kicking ability differed before versus after match play, but only for the U16 group. We found no statistically significant effects for the Precision task. Conclusions: We identified interactions between long-term and short-term soccer experience which revealed that the effects of long-term experience on affordance perception were not general. Two additional years of playing experience (in the U18 group, relative to the U16 group) did not lead to an overall improvement in the perception of kicking-related affordances. Rather, variation in long-term experience was associated with changes in affordance perception which were situation-specific, being manifested only after playing a soccer match, and not before.

Assessing decision-making in elite academy footballers using real-world video clips.

The aim of this experiment was to investigate whether there were differences in decision-making skills between different age groups (Under 16, 18 and 23) of elite academy footballers on a video-based task of real-life football scenarios. It also explored the relationship between individual performance on the task and the performance of the footballers on the pitch, as rated by three independent expert football coaches. This allowed us to examine whether this task is useful in predicting real-world decision-making skills. The results show that there was a significant difference in response times between response time was statistically significantly lower in U23 compared to U18 and U16 and there was no statistically significant difference between the U16 and the U18 groups, but no significant difference between age groups on the accuracy of response. The under 23 age group responded significantly quicker when compared to the under 18 and under 16 age group most quickly, then the U18, and finally, U16 footballers were the slowest on the task. In terms of comparing coaches' opinion about the players' decision-making skills and players performance on the task, there was a positive correlation between accuracy on the task and general decision-making skills rated by the coaches, suggesting that coaches have a good insight on what players can actually do as. However, coaches ratings of decision-making skills and response times on the task did not correlate suggesting that coaches are not aware of the speed of decision-making, and that this is only measurable by a representative task.

Landing Kinematics in Elite Male Youth Soccer Players of Different Chronologic Ages and Stages of Maturation.

Despite the high frequency of knee injuries in athletes, few researchers have studied the effects of chronologic age and stage of maturation on knee-joint kinematics in male youth soccer players. To use a coach-friendly screening tool to examine knee-valgus scores for players of different ages and at different stages of maturation. Cross-sectional study. Academy soccer clubs. A total of 400 elite male youth soccer players aged 10 to 18 years categorized by chronologic age and stage of maturation based on their years from peak height velocity (PHV). Knee valgus was evaluated during the tuck-jump assessment via 2-dimensional analysis. Frontal-plane projection angles were subjectively classified as minor (<10°), moderate (10°-20°), or severe (>20°), and using these classifications, we scored knee valgus in the tuck jump as 0 ( no valgus), 1 ( minor), 2 ( moderate), or 3 ( severe). A trend toward higher valgus scores was observed in the younger age groups and the pre-PHV group. The lowest frequency of no valgus occurred in the U18 and post-PHV groups. The highest percentages of severe scores were in the U13 and pre-PHV groups for the right limb. Knee-valgus scores were lower for both lower extremities in the U18 group than in all other age groups ( P < .001) except the U16 group. Scores were lower for the post-PHV than the pre-PHV group for the right limb ( P < .001) and both pre-PHV and circa-PHV groups for the left limb ( P < .001). Noteworthy interlimb asymmetries were evident in the U14, U15, and circa-PHV groups. Reductions in knee valgus with incremental age and during the later stages of maturation indicated that this risk factor was more prevalent in younger players. Interlimb asymmetry may also emerge around the time of the peak growth spurt and early adolescence, potentially increasing the risk of traumatic injury.

Junior cricketers are not a smaller version of adult cricketers: A 5-year investigation of injuries in elite junior cricketers

Background. Injury surveillance is fundamental to preventing and reducing the risk of injury. Objectives. To determine the incidence of injuries and the injury demographics of elite schoolboy cricketers over five seasons (2007 - 2008, 2008 - 2009, 2009 - 2010, 2010 - 2011 and 2011 - 2012). Methods. Sixteen provincial age group cricket teams (under (U) 15 , U17 and U18) competing in national age-group tournaments were provided a questionnaire to complete. The questionnaires gathered the following information for each injury sustained in the previous 12 months: (i) anatomical site; (ii) month; (iii) cause; (iv) whether it was a recurrence of an injury from a previous season; (v) whether the injury had reoccurred during the current season; and (vi) biographical data. Injuries were grouped according to the anatomical region injured. All players were invited to respond, irrespective of whether an injury had been sustained, resulting in a response rate of 57%. The sample Statistical Analysis System was used to compute univariate statistics and frequency distributions. Results. Of the 2 081 respondents, 572 (27%) sustained a total of 658 injuries. The U15 and U17 groups sustained 239 (36%) and 230 (35%) injuries, respectively, more than the 189 injuries sustained by the U18 group (29%). These injuries were predominantly to the lower limbs (38%), back and trunk (33%) and upper (26%) limbs, with 3% occurring to the head and neck. The injuries occurred primarily during 1-day matches (30%), practices (29%) and with gradual onset (21%). The primary mechanism of injury was bowling (44%) and fielding (22%). The injuries were acute (49%), chronic (41%) and acute-on-chronic (10%), with 26% and 47% being recurrent injuries from the previous and current seasons, respectively. Some similar injury patterns occurred in studies of adult cricketers, with differences in the nature and incidence of injuries found for the various age groups. The youth cricketers sustained more back and trunk injuries, recurrent injuries and more match injuries than the adult cricketers. The U15 group sustained less-serious injuries, which resulted in them not being able to play for between 1 and 7 days (58%), with more injuries occurring in the preseason period (24%) and fewer during the season (60%) compared with other age groups. The U15 and U17 groups sustained the most lumbar muscle strains, while the U18 groups sustained more serious injuries, resulting in them not being able to play for &gt;21 days. Conclusion. Young fast bowlers of all ages remain at the greatest risk of injury. Differences in the nature and incidence of injuries occurred between youth and adult cricketers, as well as in the different age groups. It is recommended that cricket administrators and coaches implement an educational process of injury prevention and management

Relative age effect and performance in the U16, U18 and U20 European Basketball Championships

ABSTRACTThis study sought to determine the association of relative age and performance of young elite basketball players. The distribution of the birth dates, heights, positions, classification and performance of the male and female participants (n = 2395) of the U16, U18 and U20 European Basketball Championships were analysed. We found an over-representation of players born during the initial months of the year in all groups, with the relative age effect being more evident in players of the U16 and U18 groups, than of the U20 teams, particularly in male squads. Nevertheless, in the U20 championships, those teams that had the oldest players performed the best. In all championships, the oldest participants played more minutes. In addition, relatively older male players scored better in total points and in performance index rating when results were normalised to played time. This effect was not found for female players. Regarding playing position, different distributions of birth dates were observed due to each position’s physical requirements. Thus, basketball coaches and managers should keep these results in mind when they select players because if not, they might subject players who are born towards the end of the year to a negative selection bias.

Junior cricketers are not a smaller version of adult cricketers: A 5-year investigation of injuries in elite junior cricketers

Background. Injury surveillance is fundamental to preventing and reducing the risk of injury. Objectives. To determine the incidence of injuries and the injury demographics of elite schoolboy cricketers over five seasons (2007 - 2008, 2008 - 2009, 2009 - 2010, 2010 - 2011 and 2011 - 2012). Methods. Sixteen provincial age group cricket teams (under (U) 15 , U17 and U18) competing in national age-group tournaments were provided a questionnaire to complete. The questionnaires gathered the following information for each injury sustained in the previous 12 months: (i) anatomical site; (ii) month; (iii) cause; (iv) whether it was a recurrence of an injury from a previous season; (v) whether the injury had reoccurred during the current season; and (vi) biographical data. Injuries were grouped according to the anatomical region injured. All players were invited to respond, irrespective of whether an injury had been sustained, resulting in a response rate of 57%. The sample Statistical Analysis System was used to compute univariate statistics and frequency distributions. Results. Of the 2 081 respondents, 572 (27%) sustained a total of 658 injuries. The U15 and U17 groups sustained 239 (36%) and 230 (35%) injuries, respectively, more than the 189 injuries sustained by the U18 group (29%). These injuries were predominantly to the lower limbs (38%), back and trunk (33%) and upper (26%) limbs, with 3% occurring to the head and neck. The injuries occurred primarily during 1-day matches (30%), practices (29%) and with gradual onset (21%). The primary mechanism of injury was bowling (44%) and fielding (22%). The injuries were acute (49%), chronic (41%) and acute-on-chronic (10%), with 26% and 47% being recurrent injuries from the previous and current seasons, respectively. Some similar injury patterns occurred in studies of adult cricketers, with differences in the nature and incidence of injuries found for the various age groups. The youth cricketers sustained more back and trunk injuries, recurrent injuries and more match injuries than the adult cricketers. The U15 group sustained less-serious injuries, which resulted in them not being able to play for between 1 and 7 days (58%), with more injuries occurring in the preseason period (24%) and fewer during the season (60%) compared with other age groups. The U15 and U17 groups sustained the most lumbar muscle strains, while the U18 groups sustained more serious injuries, resulting in them not being able to play for &gt;21 days. Conclusion. Young fast bowlers of all ages remain at the greatest risk of injury. Differences in the nature and incidence of injuries occurred between youth and adult cricketers, as well as in the different age groups. It is recommended that cricket administrators and coaches implement an educational process of injury prevention and management

A FIVE-YEAR INVESTIGATION INTO THE INCIDENCE AND NATURE OF CRICKET INJURIES IN ELITE SOUTH AFRICAN SCHOOLBOY CRICKETERS

BackgroundInjury surveillance is fundamental to understanding, preventing and reducing the risk of injury.ObjectivesThe objective was to determine the incidence of injuries sustained by elite schoolboy cricketers over five-seasons in order...

A 3-year investigation into the incidence and nature of cricket injuries in elite South African schoolboy cricketers

Objectives. Injury surveillance is fundamental to preventing and reducing the risk of injury. The aim of this study is to determine the incidence of the injuries sustained by elite schoolboy cricketers over three seasons (2007 - 2008, 2008 - 2009, 2009 -2010) to identify possible risk factors.Methods. Sixteen provincial age-group cricket teams (Under 15, Under 17 and Under 18) competing in national age-group tournaments were asked to complete questionnaires to obtain the following information for each injury: (i) anatomical site; (ii) month; (iii) cause; (iv) whether it was a recurrence of a previous injury; (v) whether the injury had reoccurred again during the season; and (vi) biographical data. Injuries were groupedaccording to the anatomical region injured. All players were requested to respond, irrespective of whether an injury had been sustained. The Sample Statistical Analysis System (SAS) was used to compute univariate statistics and frequency distributions. Of the 1 292 respondents 366 (28%) sustained a total of 425 injuries. The U15 and U17 groups sustained 166 (39%) and 148 (35%) injuries, respectively, more than the 111 injuries sustained by the U18 group (26%). These injuries were predominantly to the lower (46%) and upper (35%) limbs and occurred primarily during1-day matches (31%), practices (27%) and with gradual onset(21%). The primary mechanism of injury was bowling (45%) and fielding, including running to field the ball (33%). Forty-two lumbar muscle strains, 18 hamstring strains, 17 spondylolisthesis and 17 ankle sprains occurred. The injuries were acute (50%), chronic (42%) and acute-on-chronic (8%), with 24% and 46% being recurrent injuries from the previous and current seasons, respectively.Results. Similar injury patterns occurred in studies of adult cricketers, with slight differences in the nature and incidence of injuries found for the various age groups. The U15 group sustained less serious injuries which resulted in them not being able to play for between 1 - 7 days (54%), with more injuries occurring in the pre-season period (28%) than the other groups. The U17 group sustained the most lumbar muscle strains (n=23),while the U18 group sustained more serious injuries with 60% of the injuries resulting in them not being able to play for 8 or more days.Conclusion. Young fast-bowlers of all ages remain at the greatest risk of injury while slight differences in the nature and incidence of injuries occurred in the different age groups. It is recommended that cricket administrators and coaches need to implement an educational process of injury prevention and management.

A multidisciplinary identification model for youth handball

Talent identification in team sports is complex and requires a multidisciplinary approach. The purpose of this study was to examine differences between elite and non-elite handball players in three age groups: U14 (n=186), U16 (n=150), and U18 (n=92). A multidimensional test battery was assessed, taking biological maturation into account. Significant maturation effects were found for all anthropometric characteristics and most performance variables. Compared with their non-elite peers, the elite handball players demonstrated significantly greater aerobic capacity (P<0.01), strength and power (U14: countermovement jump, P=0.021; sit-ups, P=0.003; handgrip, P=0.020; U16: countermovement jump, P=0.013; five-jump test, P<0.001), and speed and agility (P<0.05) when maturation was controlled for. There was a significant difference in flexibility between elite and non-elite players in the U18 group (P<0.05). The elite and non-elite players did not differ in task- and ego-orientation. These results show that elite and non-elite young handball players possess different physical performance characteristics and that the specific tests that discriminate elite from non-elite handball players vary among age groups. In addition, maturity status can influence the results and should therefore be considered in talent identification and development programmes.