Effect of Biological Maturation on Performance of the Athletic Ability Assessment in Australian Rules Football Players

Purpose: To determine the effect of biological maturation on athletic movement competency as measured using the Athletic Ability Assessment-6. Methods: Fifty-two junior Australian Rules football players were split into 3 groups based on proximity to peak height velocity, while 46 senior players were split into 2 groups based on playing status. The subjects completed the Athletic Ability Assessment-6 (inclusive of the overhead squat, double lunge, single-leg Romanian dead lift, push-up, and chin-up). All subjects were filmed and retrospectively assessed by a single rater. A 1-way analysis of variance and effect-size statistics (Cohen d) with corresponding 90% confidence intervals were used to describe between-groups differences in the component movement scores. The statistical significance was set a priori at P < .05. Results: There were significant between-groups differences for all component movements (P < .05). Post hoc testing revealed that older, more mature subjects possessed greater competency in all movements except the overhead squat. The effect sizes revealed predominantly moderate to very large differences in competency between the senior and junior groups (range of d [90% confidence interval]: 0.70 [0.06 to 1.30] to 3.01 [2.18 to 3.72]), with unclear to moderate differences found when comparing the 3 junior groups (0.08 [−0.50 to 0.65] to 0.97 [0.22–1.61]). Conclusions: The findings suggest that biological maturation may be associated with changes in athletic movement competency in youth Australian Rules football players. Therefore, it is recommended that strength and conditioning coaches monitor maturity status when working with 12- to 15-y-old players. This can allow for a comparison of an individual’s athletic movement competency to maturity-based standards and help guide developmentally appropriate training programs.

Tactical rule and pitch size change the physical and technical performance of young soccer players during small-sided games

Abstract The present study examined the effects of small-sided and conditioned games (SSCGs) manipulating tactical rules (ball-possession [BP] vs goal-scoring with goalkeepers [GS]) and pitch size (square [SP] vs rectangular [RP]) on the running performance and technical skills of young soccer players. Ten male soccer players (chronological age: 12.45 ± 0.51 years; body mass: 41.99 ± 7.97 kg; height: 152.85 ± 10.03 cm) were monitored using GPS units during SSCG formats. The distance covered at different running intensities and number of technical actions were used in analyses. SSCG-induced changes in 30 m sprint and CMJ performances were also evaluated. Compared to BP, GS elicited significantly lower distances covered at low intensity running (p=0.003; d=-0.95), more sprints (p=0.050; d=0.67), and longer distances covered in terms of walking (p=0.035; d=2.60) and sprinting (p=0.029; d=0.75); (ii) number of passes (short [p=0.002; d=1.10] and long [p=0.013; d=0.82]) were more frequent during BP than GS games, while RP game format allowed for greater occurrence of long passes (p=0.036; d=0.64) than under the SP condition; (iii) jumping and sprinting performance did not change (p>0.05) using different SSCG formats. In conclusion, GS games demand more sprint running episodes in terms of number and distance covered than BP games. In addition, RP game formats can be used to increase the occurrence of longer passes in young soccer players aged 11-13 years.

The moderating impact of maturation on acute neuromuscular and psycho-physiological responses to simulated soccer activity in academy soccer players

AbstractResource constraints complicate load monitoring practices in some academies, which is problematic based on load-injury associations surrounding periods of rapid non-linear growth. Limited research has explored relationships between maturation and perceived psycho-physiological response to activity and associated neuromuscular performance changes. This study aimed to quantify neuromuscular and psycho-physiological responses to standardised activity and analyse whether dose-responses were moderated by maturation. Fifty-seven male soccer players (age: 14.1 ± 0.9 years; stature: 165 ± 10 cm; body mass, 57 ± 9 kg; percentage of predicted adult height 92.7 ± 5%) from two Elite Player Performance Plan (EPPP) academies completed the youth soccer-specific aerobic fitness test (Y-SAFT⁶⁰). Countermovement jump (CMJ), reactive strength index (RSI), absolute (ABS) and relative leg stiffness (REL) were measured pre-post the Y-SAFT⁶⁰ with playerload (PL), heart rate (HR), total distance (TD^ist) and differential ratings of perceived exertion (dRPE) used as markers of load and intensity. A moderation model was employed to analyse interactions of maturation as a continuous variable. Analysis indicated no significant interaction (p <0.05) between maturation and neuromuscular performance but RPE-Technical demonstrated significant interactions (p = 0.01). Slope analysis indicated four variables (PL, RSI, ABS and REL) that demonstrated significance at various stages of maturation, most notably aligning with peak height velocity (∼87-96% PAH). Tentatively, we propose that maturational developments in the neuromuscular system offer some mechanistic explanation to the varied dose-responses observed. It is therefore important that maturation is habitually considered within prescription of training programmes and that further empirical studies are completed to determine maturity specific dose-responses.Highlights Components of both neuromuscular performance and psycho-physiological response to simulated soccer was influenced by maturity status.Individuals more biologically developed are more capable of 'coping' with the biomechanical load of simulated soccer activity resulting in more favourable neuromuscular responses.The period surrounding peak height velocity appears to influence whole body load-response pathways resulting in altered movement patterns during this period.To minimise the impact of maturity status, practitioners can restrict activities that elicit high biomechanical load and introduce biologically categorised training activities.

Global Positioning System Analysis of Physical Demands in Small and Large-Sided Games with Floaters and Official Matches in the Process of Return to Play in High Level Soccer Players

The aim of this study was twofold: (i) to analyze the physical demands in the return to play (RTP) process of high-level soccer players in the role of floater in different soccer sided games (SGs) formats (i.e., 4vs4 + 2 and 8vs8 + 1); and (ii) to analyze the differences in physical demands encountered by regular and floater players among the SGs formats and official matches by means of global positioning system technology (GPS APEX pod, North Ireland) was used. Twenty-six highly trained, male soccer players (U16 years) participated in this investigation. Players were classified into two groups: 23 regular and 3 floater players, a total of eight SGs were analyzed, which involved the recording of 80 observations of regular and floater players. Match-play players showed most likely-probable differences in distance covered at high-intensity per minute (D > 14.4/min), at high-speed running per minute (D > 21/min), and peak velocity (Vpeak) in comparison to floaters in the 8vs8 + 1 LSG (large-side-games), and presented most likely differences in accelerations >2/min in comparison to match-play players. Therefore, the use of floaters during the last phase of the RTP (return to play) seems to be a useful strategy for progressive reintroduction into specific training (1) floater in the 4vs4 + 2 SSG; (2) floater in the 8vs8 + 1 LSG; (3) regular player in the 4vs4 + 2 SSG; and (4) regular player in the 8vs8 + 1 LSG before starting full trainings and returning to competition.

A multidisciplinary investigation into "playing-up" in academy football according to age phase

In an attempt to facilitate more appropriate levels of challenge, a common practice in academy football is to play-up talented youth players with chronologically older peers. However, the context of playing-up in academy football is yet to be empirically explored. Thus, the purpose of this study was to examine the multidimensional factors that differentiated players who play-up from those who do not. Ninety-eight participants from a single football academy were examined within their age phase: Foundation Development Phase (FDP; under-9 to under-11; n = 40) and Youth Development Phase (YDP; under-12 to under-16; n = 58). Drawing upon the FA Four Corner Model, 27 factors relating to Technical/Tactical, Physical, Psychological, and Social development were assessed. Following MANOVA analysis within both the FDP and YDP, significant differences were observed for Technical/Tactical and Social sub-components (P < 0.05). Further differences were observed for Physical and Psychological sub-components (P < 0.05) within the YDP. In sum, Technical/Tactical and Social characteristics appeared to differentiate those who play-up compared to those who do not within the FDP. In the YDP however, there were measures representing all sub-components from the FA Four Corner Model. Subsequently, it is suggested coaches and practitioners consider these holistic factors when playing-up youth football players within relevant age-phases.

Multiple athletic performances, maturation, and Functional Movement Screen total and individual scores across different age categories in young soccer players

The purpose of this study was to evaluate differences in multiple athletic performances, and to examine associations between athletic performance and Functional Movement Screen (FMS) in young soccer players. Forty-one soccer players were tested on peak height velocity (PHV), 5-, 10-, and 30-m sprint times, 505 change of direction (505 COD), Y-reactive agility tests, countermovement jump (CMJ), and squat jump (SJ) height. Significant main effects (P<0.01) were recorded in all tests except FMS total score whereas the U16 group outperformed U12 and U14 in almost each test. However, when the results were adjusted to the PHV 7 of 11 tests were nonsignificant. Significant associations were recorded between trunk stability push-up (TSPU) and 5 m (P=0.04) and 505 COD (preferred) times (P=0.01), and SJ height (P=0.03) in the U12. In the U14, significant associations were recoded between TSPU and SJ (P<0.01) and CMJ height (P=0.03). In the U16, significant associations were recorded between deep overhead squat and 5-m sprint time (P=0.02) and CMJ height (P=0.04). Results of this study indicate that athletic performance in young soccer players is multidimensional in nature, and it is a consequence of several factors including maturation, different training strategies, and movement proficiency.

A Pedagogical Approach to Integrative Neuromuscular Training to Improve Motor Competence in Children: A Randomized Controlled Trail

Font-Lladó, R, López-Ros, V, Montalvo, AM, Sinclair, G, Prats Puig, A, and Fort-Vanmeerhaeghe, A. A pedagogical approach to integrative neuromuscular training to improve motor competence in children: a RCT. J Strength Cond Res 34(11): 3078-3085, 2020-To assess the effectiveness of a pedagogical approach to an integrative neuromuscular training (INT) program as a warm-up in physical education (PE) lessons in healthy children: (a) to improve the level of motor competence (MC) and (b) to master fundamental motor skills (FMS) patterns, considering the baseline MC level and the time spent when performing different motor tasks. One hundred ninety students (7.43 ± 0.32 years; 52% girls) were included in this randomized controlled trail and grouped up according to MC basal levels (L1-L4). Motor competence and FMS patterns (CAMSA protocol) were assessed before and after the intervention in a group-based INT warm-up (n = 97) and a group-based conventional warm-up (n = 93). The INT program improved MC (p < 0.001; d = 0.71) and FMS (p < 0.001, d = 0.52). The independent predictors of MC change were: baseline MC level (β = -196; p < 0.012), time spent to perform the task (β = -0.235 p < 0.003), and participation in the INT program (β = 0.201; p < 0.005), explaining 71% of its variability. The INT warm-up shows correlations between improvements in MC in relation to time reduction (L1 p = 0.016, d, L2 p = 0.001, and L4 = 0.001) and FMS patterns (L1 p < 0.001, L2 p < 0.003, L3 p < 0.005, and L4 < 0.001) Moreover, only L3, it showed correlation between changes in time and FMS mastery (p = 0.001). Our results showed that a pedagogical approach to an INT program developed as a warm-up in primary school PE lessons can improve MC and FMS patterns in all subjects, independent of the initial MC level. More interestingly, only in L3, the improvement in MC can be explained by the balance in time required to perform the task and the level of improvement in FMS patterns.

The Effects of Strength and Conditioning in Physical Education on Athletic Motor Skill Competencies and Psychological Attributes of Secondary School Children: A Pilot Study

Leading global physical activity guidelines advocate that young children need to engage in activities that strengthen musculoskeletal tissues and improve movement skill competency. The purpose of this study was to examine the effects of delivering strength and conditioning as part of the physical education curriculum on athletic motor skill competencies (AMSC), physical performance, and psychosocial factors. Forty-six school children aged 11–14 were included in the study, and sub-divided firstly by sex and then into intervention and control groups. Intervention groups received nine lessons of strength and conditioning based activities over a six-week period, while the control groups continued with traditional physical education curricula. The resistance training skills battery (RTSB) and tuck jump assessment (TJA) assessed AMSC. Standing long jump distance assessed lower limb strength, and online surveys examined motivation, physical self-efficacy and self-esteem. Male and female intervention groups significantly improved RTSB (p > 0.05) whereas no changes were observed in the control groups. No changes were observed in the intervention groups TJA and only trivial and small non-significant changes in standing long jump performance. Significant increases in motivation of the male intervention group occurred. Strength and conditioning integrated in physical education can improve AMSC in short-term interventions.

Understanding the Development of Elite Parasport Athletes Using a Constraint-Led Approach: Considerations for Coaches and Practitioners

For the past half-century, the Paralympic Games has continued to grow, evident through increased participation, media recognition, and rising research focus in Para sport. While the competitive pool of athletes has increased, athlete development models have stayed relatively the same. Currently, coaches rely mainly on experiential knowledge, informal communication with colleagues, and theory transferred from able-bodied contexts as main resources to support development for themselves and their athletes. The purpose of this paper was to introduce Newell’s constraint-led model and its multidimensional spectrum and practical scope to address the complexities of athlete development. The model consists of three overarching constraint categories (i.e., individual, task, and environment) along with proposed additional sub-categories to capture nuances associated in Para sport in order to provide additional context to coaches regarding athlete development. Utilizing this theoretical framework, we present a holistic approach for coaches and practitioners to consider while addressing athletes’ short- and long-term developmental plans. This approach highlights the interactions among factors from a wide range of categories that indirectly and directly impact one another and ultimately influence athletes’ developmental processes. It is important to consider the dynamic interaction of constraints over various timescales during development and identify underlying issues to improve athlete experience and maximize developmental opportunities. Coaches and practitioners can use the proposed framework as a guide to key factors to consider for their cohort of athletes. This approach provides a context-specific approach that considers unique factors associated with athletes and their environment.

Determining the reliability and usability of change of direction speed tests in adolescent female soccer players: a systematic review

INTRODUCTION

This review aimed 1) to describe the most common tests used for assessing change of direction (COD) performance; 2) to detail the reliability of current COD tests; 3) to provide an overview of current intervention strategies used to improve COD performance in adolescent female soccer players.

EVIDENCE ACQUISITION

A computerized search was conducted in the PubMed, Cochrane Plus and Web of Science (from 1995 to January 2020) for English and Spanish language and peer-reviewed investigations.

EVIDENCE SYNTHESIS

A total of 221 studies were identified, with only 16 meeting the specific search criteria. The main findings were that eleven different tests have been used to assess COD performance with intraclass correlation coefficient and coefficient of variation values between 0.72-0.99 and 1-10.6%, respectively. The number of CODs performed during each test ranged from 1 to 9 within a range of 45º to 180º and with a duration <5 s, 5-9 s and >10 s.

CONCLUSIONS

Findings indicate that the reliability of the COD tests seems to depend on: the equipment used, the surface tested on and the technical level of the soccer player. These results should be interpreted with caution as they may be influenced by the period of growth and maturation, the playing position of the player and the period of the soccer season. Finally, strength and power drills could be considered as appropriate to improve COD performance.

Constructing a Talent Identification Index System and Evaluation Model for Cross-Country Skiers

A talent identification index system for male and female cross-country skiers in four age groups (11-12 years old, 13-14 years old, 15-16 years old, and 17-18 years old) was established. The system comprises five body shape indexes ( i =5): Leg-to-Body Ratio (LBR), body fat percentage, maturity status, spreaded brachia index, and upper extremity length. The physiological function indexes ( i =2) are VO_2max and haemoglobin mass (Hb). The psychological indexes ( i =5) cover reaction time, perception speed, a quality-of-will scale, an attention test, and operational thinking. The physical fitness indexes ( i =11) comprise upper limb explosiveness, vertical jump, 3000-metre run, orthostatic forward flexion, closed-eyes single-leg stand, standing long jump, 20-metre sprint, pull-ups (males), flexed arm hang (females), hexagon jump, and a Functional Movement Screen (FMS) test. The athletic performance indexes ( i =3) comprise on-snow time trials for 1.2 km, 5 km, and 10 km. The talent identification evaluation model was created using automated evaluation software. The talent identification index system and evaluation standard table for cross-country skiers passed the P₆₀ shortlist and P₉₀ elite boundaries established using the percentile method. Thus, the results of this test profile verify that the evaluative model is objectively effective.

Changes in the Growth and Development of Adolescents in a Country in Socio-Economic Transition 1993-2013

Introduction

Changes in human growth and development depend on genetic and environmental factors. In the case of Slovenia, the environmental factors changed as a result of the period of socio-economic transition that the country underwent between 1991 and 2013. The authors used anthropometric techniques to evaluate differences in body height, proportions and sexual maturity in 1,221 adolescents aged 14 in 1993, 2003 and 2013.

Methods

Data was collected as a part of the ACDSi study, which has monitored children’s somatic growth and motor development every decade over the last 40 years.

Results

Between 1993 and 2013, a trend (p=0.08) towards increased body height was observed in males. The comparison of age at peak height velocity (PHV) between generations demonstrated a trend (p=0.07) of earlier entry into puberty in adolescents in 2013 compared to those in 1993. The leg-to-body height ratio increased (p<0.05) with every decade in males, while in females it decreased (p<0.05) in 2013. Similar trends were observed in the leg-to-trunk ratio. Contemporary generations experienced PHV at a younger age (p<0.05), which is true for both genders even in adolescents born no more than two decades (1993 (2013) apart. In both generations, females experienced PHV sooner than their male peers.

Conclusion

The authors assume that females of the 2013 generation reached puberty earlier than females of older generations. It is most likely that, unlike females from older generations and unlike males, they were already at the stage of trunk growth at the time of the measurements, which explains the observed changes in their trunk length, leg-to-body height and leg-to-trunk ratios in comparison to earlier generations.

Differences in Maturity, Morphological, and Fitness Attributes Between the Better- and Lower-Ranked Male and Female U-14 Portuguese Elite Regional Basketball Teams

Ramos, S, Volossovitch, A, Ferreira, AP, Barrigas, C, Fragoso, I, and Massuça, L. Differences in maturity, morphological and fitness attributes between the better- and lower-ranked male and female U-14 Portuguese elite regional basketball teams. J Strength Cond Res 34(3): 878-887, 2020-During a national championship, the anthropometric, physiological, and maturation attributes of 13-14-year-old players of regional selection basketball teams and their association with team's final classification were analyzed. Body parameters (body mass, height, skinfolds, and lengths) were measured and physiological capacities assessed by sprint (20 m), agility, jump, and upper-body strength tests. Chronological age, maturity offset (years from age at peak height velocity; YAPHV), and predicted age at peak height velocity were calculated. In both sexes, no significant differences were found for maturity. Anthropometric and physiological analysis indicated that male players from finalist's teams were significantly faster, were more agile, threw the medicine ball longer, and showed lower percentages of body fat than players from lower-ranked teams. Further, semifinalists were faster than lower-ranked players. In the same sense, female players from semifinalist teams demonstrated to be significantly faster, more agile, and threw the medicine ball longer than female players from lower-ranked teams. In addition, discriminant analysis showed that speed (in boys) and the combination of speed and upper limb strength (in girls) could successfully discriminate players with different performances in a championship. In conclusion, speed and upper limb strength appear to be the physical attributes associated with better team performance in youth basketball. Coaches should be aware of the relationship between the improvement of these physical attributes and the teaching-learning process of the basketball game.

Effects of long-term athletic training on muscle morphology and tendon stiffness in preadolescence: association with jump performance

Purpose

Evidence on training-induced muscle hypertrophy during preadolescence is limited and inconsistent. Possible associations of muscle strength and tendon stiffness with jumping performance are also not investigated. We investigated the thickness and pennation angle of the gastrocnemius medialis muscle (GM), as indicators for potential muscle hypertrophy in preadolescent athletes. Further, we examined the association of triceps surae muscle–tendon properties with jumping performance.

Methods

Eleven untrained children (9 years) and 21 similar-aged artistic gymnastic athletes participated in the study. Muscle thickness and pennation angle of the GM were measured at rest and muscle strength of the plantar flexors and Achilles tendon stiffness during maximum isometric contractions. Jumping height in squat (SJ) and countermovement jumps (CMJ) was examined using a force plate. We evaluated the influence of normalised muscle strength and tendon stiffness on jumping performance with a linear regression model.

Results

Muscle thickness and pennation angle did not differ significantly between athletes and non-athletes. In athletes, muscle strength was greater by 25% and jumping heights by 36% (SJ) and 43% (CMJ), but Achilles tendon stiffness did not differ between the two groups. The significant predictor for both jump heights was tendon stiffness in athletes and normalised muscle strength for the CMJ height in non-athletes.

Conclusion

Long-term artistic gymnastics training during preadolescence seems to be associated with increased muscle strength and jumping performance but not with training-induced muscle hypertrophy or altered tendon stiffness in the plantar flexors. Athletes benefit more from tendon stiffness and non-athletes more from muscle strength for increased jumping performance.

Longitudinal development of 5m sprint performance in young female tennis players

Sprint performance over short distances is a central component in young tennis players' development. This study aimed to examine the longitudinal development of sprint performance in young female tennis players, and to investigate differences between performance levels. Also potentially explanatory variables were investigated. Female tennis players aged 10-15 (N = 167) participated in a, mixed-longitudinal study (n = 48 elite; n = 119 sub-elite). Players were measured annually on the 5 m sprint as well as for possible explaining variables for 5 m sprint performance development (age, height, body mass, maturity status, lower limb explosive strength). Multilevel analysis was used to obtain a developmental model. Moreover, it was possible to predict sprint performance (5 m) based on chronological age, body size given by height, and lower limb strength performance (p < .05). Significant different developmental patterns were found for elite and sub-elite players, with elite players aged 10-14 being faster. After age 14, no significant differences were found in sprint performance between elite and sub-elite players (p > . 05). Sprint performance is an important characteristic of young female tennis players and seemed to depend on growth and maturation in parallel to physical fitness.

Rehabilitation of Watson-Jones proximal tibial avulsion injury in elite academy level football: A report of two separate cases in one season

OBJECTIVES

Watson-Jones proximal tibial avulsion injuries occur more frequently in athletic and muscular adolescent males. However, they are rare and therefore infrequently described in the medical literature. Two of these injuries occurred in a Category 1 football academy in the same season within a six-month period. We have described the cases with the hope of better informing other clinicians should they encounter this injury.

METHODS

This case report describes the injury mechanism, surgical management and rehabilitation for the two cases [Players A and B]. Outcomes measures including player speed, agility and power were compared with scores from players of the same age group at the time of injury in the Premier League academies. Risk factors are also discussed.

RESULTS

Both players were managed surgically, initially. Player B had the surgical fixation removed during rehabilitation. Player A still has the fixation in situ. Post-surgery, player A returned to full play at thirty-two weeks and thirty-eight weeks for player B. No critical incidents occurred during rehabilitation.

CONCLUSION

Watson-Jones avulsion fractures, although rare, can be managed successfully. Athletes can achieve a successful return to play at their previous level.

Physical Performance in Young Judo Athletes: Influence of Somatic Maturation, Growth, and Training Experience

Purpose: To determine the individual contributions of chronological age, somatic maturation, body size and composition, and training experience as indicators of performance in neuromuscular and judo-specific assessments in young athletes. Methods: Sixty-six youth judo athletes performed anthropometric measurements, neuromuscular tests-standing long jump test (SLJ), medicine ball throw test (MBT), handgrip strength test (HGS), and judo-specific tests-Special Judo Fitness test (SJFT) and Judogi Grip Isometric Strength Test (JGST_ISO). A multiple linear regression was used with the level of significance set at 5%. Results: The main results showed age-peak height velocity (PHV), body fat and training experience explained close to 20% of SJFT performance. Chronological age, age-PHV, height, body mass and body fat accounted for 42% of variance in JGST_ISO. Chronological age, body fat and training experience explained 35% of the variance in SLJ, while chronological age, body mass and body fat explained 53% of the variance in MBT. Finally, age-PHV, body mass and height explained 54% of the variance in HGS. Conclusion: Estimated age-PHV and growth variables explained moderate to large proportions of the variance in neuromuscular tests (with exception of SLJ), while both estimated age-PHV, training and growth variables were predictors of judo-specific performance.

Effects of Combined Strength and Power Training on Physical Performance and Interlimb Asymmetries in Adolescent Female Soccer Players

PURPOSE

To examine the effects of an 8-week combined strength and power training intervention on physical performance and interlimb asymmetries in adolescent female soccer players.

METHODS

Thirty-seven adolescent female soccer players (age 16.1 [1.1] y) were randomly assigned to a control group (n = 18) or experimental group (n = 19). The experimental group performed combined strength and power training twice a week, which consisted of strength and power exercises that trained the major muscles of the lower body and trunk musculature. Preintervention and postintervention tests included unilateral and bilateral horizontal and countermovement jump tests, a 40-m sprint test (10- and 30-m split times), a 10-m sprint with a 180° change-of-direction (COD) test, and a multiple-COD test (V-cut test). Asymmetries were also analyzed in the unilateral tests.

RESULTS

Significant group-by-time interaction of the improvement between pretest and posttest was observed for speed (effect size [ES]: -1.30 to -1.16) and COD tests (ES: -0.62 to -0.61) but not in jumping (ES: -0.09 to 0.28) and interlimb-asymmetry tests (ES: -0.13 to 0.57).

CONCLUSIONS

The short-term in-season combined strength and power training program induced greater speed and COD performance improvements than soccer training alone in adolescent female soccer players.

Maturation-, age-, and sex-specific anthropometric and physical fitness percentiles of German elite young athletes

The aim of this study was to establish maturation-, age-, and sex-specific anthropometric and physical fitness percentile reference values of young elite athletes from various sports. Anthropometric (i.e., standing and sitting body height, body mass, body mass index) and physical fitness (i.e., countermovement jump, drop jump, change-of-direction speed [i.e., T-test], trunk muscle endurance [i.e., ventral Bourban test], dynamic lower limbs balance [i.e., Y-balance test], hand grip strength) of 703 male and female elite young athletes aged 8-18 years were collected to aggregate reference values according to maturation, age, and sex. Findings indicate that body height and mass were significantly higher (p<0.001; 0.95≤d≤1.74) in more compared to less mature young athletes as well as with increasing chronological age (p<0.05; 0.66≤d≤3.13). Furthermore, male young athletes were significantly taller and heavier compared to their female counterparts (p<0.001; 0.34≤d≤0.50). In terms of physical fitness, post-pubertal athletes showed better countermovement jump, drop jump, change-of-direction, and handgrip strength performances (p<0.001; 1.57≤d≤8.72) compared to pubertal athletes. Further, countermovement jump, drop jump, change-of-direction, and handgrip strength performances increased with increasing chronological age (p<0.05; 0.29≤d≤4.13). In addition, male athletes outperformed their female counterpart in the countermovement jump, drop jump, change-of-direction, and handgrip strength (p<0.05; 0.17≤d≤0.76). Significant age by sex interactions indicate that sex-specific differences were even more pronounced with increasing age. Conclusively, body height, body mass, and physical fitness increased with increasing maturational status and chronological age. Sex-specific differences appear to be larger as youth grow older. Practitioners can use the percentile values as approximate benchmarks for talent identification and development.

Effects of Hoverboard on Balance in Young Soccer Athletes

Hoverboards are always more popular among children. Hoverboards are to them like a game or a mean of transport, but they could be used as a valid and useful instrument in children's training programs to improve their performance. In this study, we compared the athletic performance of two groups of 12 children. A total of 24 children aged between 8 and 11 years followed a similar training program for five months, but the first group used a hoverboard (Hb+ group: Age: Standard Deviation (SD) = 1.15 Mean = 9.66; Weight: SD = 5.90 Mean = 32; Height: SD = 7.64 Mean = 135.08) for some of the training time, differently from the second group (Hb- group: Age: SD = 1.15 Mean = 9.66; Weight: SD = 5.82 Mean = 31.16; Height: SD = 7.66 Mean = 136.16), which never used it. All of the children were asked to complete three tests (one leg test, stork test and balance beam walking test) before starting their own training program and after five months, to evaluate how their performances changed in terms of time. Comparing the recorded time difference between T0 and T1 of the Hb+ group with the same difference measured in Hb- group, it was found that there was a statistically significant difference (p value < 0.05) between these data for all three tests. Children who used the hoverboard in their training program achieved better result than children who did not use it. In the future, the hoverboard could help athletes to improve their performances, possibly applying it not only in football training, but even in other sports.

Effects of Resistance Training on Change-of-Direction Speed in Youth and Young Physically Active and Athletic Adults: A Systematic Review with Meta-Analysis

BACKGROUND

Change-of-direction (CoD) speed is a physical fitness attribute in many field-based team and individual sports. To date, no systematic review with meta-analysis available has examined the effects of resistance training (RT) on CoD speed in youth and adults.

OBJECTIVE

To aggregate the effects of RT on CoD speed in youth and young physically active and athletic adults, and to identify the key RT programme variables for training prescription.

DATA SOURCES

A systematic literature search was conducted with PubMed, Web of Science, and Google Scholar, with no date restrictions, up to October 2019, to identify studies related to the effects of RT on CoD speed.

STUDY ELIGIBILITY CRITERIA

Only controlled studies with baseline and follow-up measures were included if they examined the effects of RT (i.e., muscle actions against external resistances) on CoD speed in healthy youth (8-18 years) and young physically active/athletic male or female adults (19-28 years).

STUDY APPRAISAL AND SYNTHESIS METHODS

A random-effects model was used to calculate weighted standardised mean differences (SMD) between intervention and control groups. In addition, an independent single training factor analysis (i.e., RT frequency, intensity, volume) was undertaken. Further, to verify if any RT variable moderated effects on CoD speed, a multivariate random-effects meta-regression was conducted. The methodological quality of the included studies was assessed using the physiotherapy evidence database (PEDro) scale.

RESULTS

Fifteen studies, comprising 19 experimental groups, were included. The methodological quality of the studies was acceptable with a median PEDro score of 6. There was a significant large effect size of RT on CoD speed across all studies (SMD = - 0.82 [- 1.14 to - 0.49]). Subgroup analyses showed large effect sizes on CoD speed in males (SMD = - 0.95) contrasting with moderate improvements in females (SMD = - 0.60). There were large effect sizes on CoD speed in children (SMD = - 1.28) and adolescents (SMD = - 1.21) contrasting with moderate effects in adults (SMD = - 0.63). There was a moderate effect in elite athletes (SMD = - 0.69) contrasting with a large effect in subelite athletes (SMD = - 0.86). Differences between subgroups were not statistically significant. Similar improvements were observed regarding the effects of independently computed training variables. In terms of RT frequency, our results indicated that two sessions per week induced large effects on CoD speed (SMD = - 1.07) while programmes with three sessions resulted in moderate effects (SMD = - 0.53). For total training intervention duration, we observed large effects for ≤ 8 weeks (SMD = - 0.81) and > 8 weeks (SMD = - 0.85). For single session duration, we found large effects for ≤ 30 min and ≥ 45 min (both SMD = - 1.00). In terms of number of training sessions, we identified large effects for ≤ 16 sessions (SMD = - 0.83) and > 16 sessions (SMD = - 0.81). For training intensity, we found moderate effects for light-to-moderate (SMD = - 0.76) and vigorous-to-near maximal intensities (SMD = - 0.77). With regards to RT type, we observed large effects for free weights (SMD = - 0.99) and machine-based training (SMD = - 0.80). For combined free weights and machine-based training, moderate effects were identified (SMD = - 0.77). The meta-regression outcomes showed that none of the included training variables significantly predicted the effects of RT on CoD speed (R2 = 0.00).

CONCLUSIONS

RT seems to be an effective means to improve CoD speed in youth and young physically active and athletic adults. Our findings indicate that the impact of RT on CoD speed may be more prominent in males than in females and in youth than in adults. Additionally, independently computed single factor analyses for different training variables showed that higher compared with lower RT intensities, frequencies, and volumes appear not to have an advantage on the magnitude of CoD speed improvements. In terms of RT type, similar improvements were observed following machine-based and free weights training.

Monitoring physical and motor traits in primary school: a local harmful situation for older children

BACKGROUND

Health-related testing in school environments may be led by PE lessons facilities, which represent an optimal context. Aiming to investigate the developmental trajectories of physical and motor traits during PE lessons, we recruited 381 children in grades 1, 2, 4 and 5 of primary school in Abruzzo, Italy.

METHODS

We included anthropometric indexes (Body Mass Index and Waist-to-Height Ratio) and fitness tests, i.e. 4×10 m Shuttle Run test (4×10 SR), handgrip strength test, and standing long jump test (LJ). We also included two fine motor skills (FMS) tests and collected data about sports participation.

RESULTS

Gender differences were found about sports participation (boys were more involved in open-skills sports) and motor skills, with girls outperforming boys in FMS and vice versa in fitness measures, even if with small evidence. There was an increment in all the tests with age, with the most robust evidence about handgrip strength and FMS. School clustering had a significant random effect on some fitness measures (4×10 SR and LJ). Despite high sports participation, an impairment in older children was detected, with a special alarm in older boys about metabolic risk.

CONCLUSIONS

The small-to-moderate correlations between parameters suggest that there are similarities in the developmental trajectories, but also that it should be assessed a wide range of motor skills and anthropometric indexes. In conclusion, we support the assessment of gender-and-context-related developmental trajectories in the school setting, by the mean of fitness measures, anthropometric indexes, and FMS, to be compared with local and general references, as evidence-based planning of PE interventions.

Effect of somatic maturity on the aerobic and anaerobic adaptations to sprint interval training

The purpose of this study was to assess the maturity-related differences in the aerobic and anaerobic adaptations to sprint interval training (SIT) among youth male athletes. Twenty-seven youth male athletes were assessed for years from peak height velocity (PHV) and classified into prepubescent (PRE, n = 7, years from PHV = -2.21 ± 0.47 years), peripubescent (PERI, n = 10, years from PHV = 0.25 ± 0.88 years), and postpubescent (POST, n = 10, years from PHV = 2.81 ± 0.50 years) groups based on their years from estimated peak height velocity. Participants completed a ramp exercise protocol on a cycle ergometer to determine maximal aerobic power, maximal oxygen consumption (VO2peak ), and fatigue thresholds. Following baseline, all participants completed a 4-week SIT program that consisted of eight total training sessions. During each session, participants completed repeated 20-s sprints on a cycle ergometer against a resistance of 7.5% of body mass. The number of sprints per sessions increased from four in session 1 to seven in session 7, with four sprints in session 8. Peak and mean power from sessions 1 and 8 were recorded. All participants completed a post-testing ramp exercise protocol that mirrored baseline. Maximal aerobic power increased (p < .001) across all groups from baseline (212.61 ± 57.45 W) to post-testing (223.24 ± 58.90 W); however, VO2peak only increased in POST (3.31 ± 0.43 to 3.54 ± 0.43 L min-1 , p = .003). Similarly, GET, VT, and RCP increased in POST, with no changes in PRE or PERI. In terms of anaerobic performance, PERI and POST had significant increases in peak and mean power. POST improved aerobic and anaerobic performance following SIT, while PERI only experienced improvements in anaerobic performance. Conversely, PRE had no changes in aerobic or anaerobic performance. The adaptations to SIT appear to be influenced by the somatic maturity status.

Reliability of Change of Direction and Agility Assessments in Youth Soccer Players

Considering the vast physical and neural developments experienced throughout adolescence, the reliability of physical performance may vary in youth populations. This study aimed to examine the reliability of change of direction (COD) and agility tests in youth soccer players. Altogether, 86 youth soccer players, aged 13.6 ± 2.0 years, volunteered to participate. Data were collected from a modified 505 COD test (m505COD) and the Y-sprint drill in both pre-planned (Y-SprintPRE) and reactive (Y-SprintREACT) conditions during 2 sessions, 7 days apart. Anthropometric data including body mass, standing stature, and sitting height were also collected. COD and agility tests demonstrated good reliability (ICC = 0.81-0.91; CV = 1.2-2.0; d = 0.00-0.31; p < 0.01) for our entire sample. However, we observed a small negative relationship between age and intersession differences for the Y-SprintPRE (r = -0.28; p = 0.04), and moderate negative relationships between both age (r = -0.41; p < 0.01), and maturity offset (r = -0.39; p < 0.01) for the Y-SprintREACT. Although the COD and agility tests adopted within this study possess good intersession reliability, we observed greater intersession differences for younger and less mature individuals. We suggest that while COD and agility tests may provide meaningful objective data for monitoring the development of youth soccer players, these tests should be used with caution when evaluating younger, more immature athletes.

Movement Competency Training Delivery: At School or Online? A Pilot Study of High-School Athletes

Movement competency (MC) development of high-school athletes can prepare them for the requirements of physical preparation training and the demands of sport. The aim of this study was to explore the physical effects of and athlete compliance to coach-led versus self-directed training approaches in this population. Thirty-nine high-school athletes (19 male, 14.5 ± 0.3 years old; 20 female, 14.6 ± 0.3 years) were allocated into two groups for a physical preparation program to improve MC. Groups were prescribed either (i) one face-to-face and one online (F2F, n = 18), or (ii) two online (OL, n = 21) sessions per week for 16-weeks. Before and after the intervention, the Athlete Introductory Movement Screen (AIMS) was used to assess MC alongside common physical capacity measures (triple-hop, star-excursion balance, medicine ball throw, 40m sprint and countermovement jump). Dropout left 22 participants with pre-post physical scores. Compliance with online training was low and F2F session attendance moderate. Semi-structured interviews were conducted to assess participant perceptions following the intervention. Assessing individual responses, the F2F group had a higher proportion of positive responders to AIMS scores, yet capacity measures were inconclusive across groups. Face-to-face coaching when acquiring MCs as part of physical preparation, may provide greater positive perceptions towards training compared to self-directed online prescriptions, and thereby greater compliance.

Effects of Combined Resistance Training and Weightlifting on Motor Skill Performance of Adolescent Male Athletes

Pichardo, AW, Oliver, JL, Harrison, CB, Maulder, PS, Lloyd, RS, and Kandoi, R. Effects of combined resistance training and weightlifting on motor skill performance of adolescent male athletes. J Strength Cond Res 33(12): 3226-3235, 2019-Resistance training and weightlifting are regarded as safe and effective training methods for youth. However, no studies have examined the effects of a year-long resistance training program using weightlifting movements on strength, speed, or power. Therefore, the purpose of this study was to determine the long-term effects of combined resistance training (traditional strength training + plyometrics) with or without weightlifting movements on motor skill performance of adolescent males. Fifty-nine males aged 12-14 years were matched by maturity and allocated to a combined resistance training or a combined resistance training with weightlifting group. Each group completed 28 total weeks of training over an academic year. Pre-, mid- (14 weeks of training), and post-training (28 weeks of training) tests included the resistance training skills battery quotient (RTSQ), absolute isometric midthigh pull peak force (IMTPABS) and ratio-scaled isometric midthigh pull peak force (IMTPREL), countermovement jump, horizontal jump, and 10-, 20-, and 30-m sprint. Repeated-measure analysis of variance revealed that there were no significant between-group responses, but all variables improved significantly within-group. Both groups made small-moderate improvements in RTSQ, IMTPABS, and IMTPREL after the first 14 training weeks (d = 0.45-0.86), whereas small-moderate improvements in lower body power, upper body power, and speed were made after the second 14 training weeks (d = 0.30-0.95). Both groups made small-moderate improvements in all performance variables after 28 weeks of training. These findings highlight the importance of establishing movement competency and strength as a foundation for the subsequent development of power. Furthermore, these findings may help practitioners understand the time course of certain adaptations following a long-term periodized plan for adolescent males.

Seasonal Effects of Strength Endurance vs. Power Training in Young Female Soccer Athletes

Lesinski, M, Prieske, O, Chaabene, H, and Granacher, U. Seasonal effects of strength endurance vs. power training in young female soccer athletes. J Strength Cond Res XX(X): 000-000, 2020-This study examined the seasonal effects of strength endurance training (SET) vs. power training (PT) on physical fitness and body composition in young female soccer players. Thirty-six young female elite soccer players (15 ± 1 years; maturity offset +3 ± 1 years) were allocated to progressive SET (n = 19) or PT (n = 17). Over the course of one soccer season, SET performed slow movement velocity, moderate intensity (50-60% of the 1 repetition maximum [1RM]; 20-40 repetitions) strength exercises while PT performed moderate-to-high intensity (50-95% of the 1RM; 3-8 repetitions), high movement velocity strength exercises (2 sessions·wk). Before and after training, tests were performed for the assessment of muscle strength (1RM leg press), jump performance (countermovement jump [CMJ], drop jump [DJ]), muscular endurance (ventral Bourban test), linear speed (10 m, 20 m), change-of-direction (CoD) speed (T-test), dynamic balance (Y-balance test), sport-specific performance (kicking velocity), and body composition (lean body mass and fat mass). An analysis of covariance was used to test for between-group differences at post-test with baseline values as covariate. No significant between-group differences were observed in terms of total training volume over the respective soccer seasons (p = 0.069; d = 0.68). At post-test, SET showed significantly better ventral Bourban and T-test performances (d = 1.28-2.28; p = 0.000-0.001) compared with PT. However, PT resulted in significantly better 1RM leg press, DJ, 10-m, and 20-m sprint performances (d = 0.85-1.44; p = 0.000-0.026). No significant between-group differences were observed at post-test for CMJ, Y-balance test, kicking performance, and body composition (d = 0.20-0.74, p = 0.051-0.594). Our findings are mainly in accordance with the principle of training specificity. Both SET and PT are recommended to be implemented in young female elite soccer players according to the respective training period.

Gastrocnemius Medialis Architectural Properties in Flexibility Trained and Not Trained Child Female Athletes: A Pilot Study

Gastrocnemius medialis (GM) architecture and ankle angle were compared between flexibility trained (n = 10) and not trained (n = 6) female athletes, aged 8–10 years. Ankle angle, fascicle length, pennation angle and muscle thickness were measured at the mid-belly and the distal part of GM, at rest and at the end of one min of static stretching. Flexibility trained (FT) and not trained athletes (FNT) had similar fascicle length at the medial (4.19 ± 0.37 vs. 4.24 ± 0.54 cm, respectively, p = 0.841) and the distal part of GM (4.25 ± 0.35 vs. 4.18 ± 0.65 cm, respectively, p = 0.780), similar pennation angles, and muscle thickness (p > 0.216), and larger ankle angle at rest (120.9 ± 4.2 vs. 110.9 ± 5.8°, respectively, p = 0.001). During stretching, FT displayed greater fascicle elongation compared to FNT at the medial (+1.67 ± 0.37 vs. +1.28 ± 0.22 cm, respectively, p = 0.048) and the distal part (+1.84 ± 0.67 vs. +0.97 ± 0.97 cm, respectively, p = 0.013), larger change in joint angle and muscle tendon junction displacement (MTJ) (p < 0.001). Muscle thickness was similar in both groups (p > 0.053). Ankle dorsiflexion angle significantly correlated with fascicle elongation at the distal part of GM (r = −0.638, p < 0.01) and MTJ displacement (r = −0.610, p < 0.05). Collectively, FT had greater fascicle elongation at the medial and distal part of GM and greater MTJ displacement during stretching than FNT of similar age.

Efficacy of School-Based Interventions for Improving Muscular Fitness Outcomes in Adolescent Boys: A Systematic Review and Meta-analysis

BACKGROUND

It has been reported that boys' and girls' physical activity (PA) levels decline throughout adolescence. Boys are at risk of physical inactivity during adolescence; however, in intervention research, they are an under-represented group relative to girls. It is suggested that the school environment may be central to developing interventions that support adolescents in meeting the current PA guidelines. The aim of this systematic review and meta-analysis was to investigate the efficacy of school-based physical activity interventions for improving muscular fitness (MF) in adolescent males.

METHODS

This systematic review and meta-analysis followed the preferred reporting systems for meta-analyses guidelines and was registered on PROSPERO (Registration number: CRD42018091023). Eligible studies were published in English within peer-reviewed articles. Searches were conducted in three databases, with an additional grey literature search in Google Scholar. Studies investigating MF outcomes were included.

RESULTS

There were 43 data sets identified across 11 studies, from seven countries. Overall methodological quality of the studies was moderate-to-strong. Interventions targeting MF evidenced a small-to-medium effect (g = 0.32, CI 0.17, 0.48, p < 0.00). Subgroup analyses of MF delivery method resulted in small-to-medium effects: upper limb MF measures (g = 0.28, 95% CI - 0.02, 0.58, p = 0.07), lower limb MF measures (g = 0.28, 95% CI 0.09, 0.68, p = 0.03), combined MF activities (g = 0.24, 95% CI - 0.04 to 0.49, p = 0.05), plyometric activities (g = 0.39, 95% CI 0.09, 0.68, p = 0.01), body weight (g = 0.27, 95% CI - 0.10, 0.65, p = 0.15), and traditional MF methods (g = 0.43, 95% CI 0.09, 0.78, p = 0.01).

CONCLUSIONS

School-based interventions which aimed to increase MF outcomes in adolescent boys demonstrated small-to-moderate effects. Traditional and plyometric methods of resistance training appear to be the most effective form of PA delivery in adolescent males. More quality research is required to assess the impact of MF delivered in the school environment to inform future intervention design.

Anthropometric, Body Composition, and Morphological Lower Limb Asymmetries in Elite Soccer Players: A Prospective Cohort Study

The aim of this study was to identify and compare parameters related to anthropometry, body composition (BC), and morphological asymmetry in elite soccer players in nine age categories at the same soccer club (n = 355). We used a bio-impedance analyzer to measure the following indicators of BC: body height (BH); body mass (BM); relative fat-free mass (FFMr); percentage of fat mass (FM); and bilateral muscle mass differences in the lower extremities (BLD∆). Age showed a significant influence on all parameters observed (F_64,1962 = 9.99, p = 0.00, λ = 14.75, η²_p = 0.25). Adolescent players (from U16 through adults) had lower FM values (<10%) compared to players in the U12-U15 categories (>10%). The highest FFMr was observed in the U18 category. Players in the U12 and U13 categories showed more homogenous values compared to older players. With increasing age, significantly higher FFMr was observed in the lower extremities. An inter-limb comparison of the lower extremities showed significant differences in the U17 category (t₂₇ = 2.77, p = 0.01) and in adult players (t₆₈ = 5.02, p = 0.00). Our results suggest that the end of height growth occurs around the age of 16 years, while weight continues to increase until 20 years. This increase is not linked to decreasing FM, nor to the FFMr, which remains stable. We found morphological asymmetries between limbs in players of the U17 category and in adult players.

Change of Direction Performance in Young Tennis Players: A Comparative Study Between Sexes and Age Categories

Fernandez-Fernandez, J, Loturco, I, Pereira, LA, Del Coso, J, Areces, F, Gallo-Salazar, C, and Sanz-Rivas, D. Change of direction performance in young tennis players: a comparative study between sexes and age-categories. J Strength Cond Res XX(X): 000-000, 2019-The aim of this study was to examine the differences in linear sprint, change of direction (COD) performance, and COD deficit in a large sample of under-13 (U13) and under-15 (U15) male and female tennis players. One hundred and twenty-eight junior tennis players grouped into 2 age-groups (U13 years [32 boys and 28 girls] and U15 [36 boys and 32 girls]) participated in this study. Tests included anthropometric measurements, sprints (5-, 10- and 20-m), and a modified version of the 505 COD test. The differences in performance between age-categories and sex were assessed via an independent t-test. The differences in the physical tests between U13 and U15 players were tested using a univariate analysis, with age and anthropometric variables as covariates. Effect sizes (ESs) were calculated for pairwise comparisons. Results showed that boys presented lower 20-m sprint times than girls in the U13 (ES: 0.54; p < 0.05), and lower linear sprint (5-20-m) and COD times than girls in the U15 category (ES varying from 0.67 to 1.60; p < 0.05). Comparing age-groups, U15 girls demonstrated a higher COD deficit than the U13 (p < 0.05), whereas no differences were found in the other variables. In boys, no significant differences were observed in any variable when comparing both categories. These results could be of great interest for coaches and researchers involved in the development and training of elite tennis players, suggesting the need to include strategies able to improve sprint and COD performance throughout the players' specialization process.

Influence of biological maturation on speed, jump, and endurance in high-level youth soccer players

ABSTRACT The goal of this study is to identify the influence of the maturity state in the physical components of the high level youth male soccer players of an elite club in Brazil. Eighty-seven young male soccer players participated in this study, distributed in 34 U-14 players, 23 U-16 players and 30 U-19 players. Peak height velocity (PHV) was estimated: Pre-PHV (<-1.0 years, n=13), mid-PHV (-0.99 to 0.5 years, n=41), and post-PHV (>0.5 years, n=33). Running-based anaerobic sprint test, squat jump, yo-yo and 30m speed test were performed. The results of this study suggest that the maturational development influences vertical jump. VO2max, yo-yo test distance, fatigue index and power. This information is essential for the identification and effective development of talented football players.

Eccentric Resistance Training in Youth: Perspectives for Long-Term Athletic Development

The purpose of this narrative review is to discuss the role of eccentric resistance training in youth and how this training modality can be utilized within long-term physical development. Current literature on responses to eccentric exercise in youth has demonstrated that potential concerns, such as fatigue and muscle damage, compared to adults are not supported. Considering the importance of resistance training for youth athletes and the benefits of eccentric training in enhancing strength, power, speed, and resistance to injury, its inclusion throughout youth may be warranted. In this review we provide a brief overview of the physiological responses to exercise in youth with specific reference to the different responses to eccentric resistance training between children, adolescents, and adults. Thereafter, we discuss the importance of ensuring that force absorption qualities are trained throughout youth and how these may be influenced by growth and maturation. In particular, we propose practical methods on how eccentric resistance training methods can be implemented in youth via the inclusion of efficient landing mechanics, eccentric hamstrings strengthening and flywheel inertia training. This article proposes that the use of eccentric resistance training in youth should be considered a necessity to help develop both physical qualities that underpin sporting performance, as well as reducing injury risk. However, as with any other training modality implemented within youth, careful consideration should be given in accordance with an individual's maturity status, training history and technical competency as well as being underpinned by current long-term physical development guidelines.