Assessment of elite junior tennis serve and return practice: A cross-sectional observation.

Practice tasks that more closely represent the demands of competition are thought to augment skill learning and transfer. This study observed the serve and return performances of junior grand slam tennis and used this benchmark to evaluate the representativeness of serve and return practice among elite junior tennis players. The serve and return behaviour of 26 junior tennis players competing in junior Australian Open grand slam matches were observed and compared with the serve and return practice behaviours of 12 elite junior tennis players over an 8-week period. The variables measured included the number of serves/returns landing in, serve/return type, serve direction and the variability of practised skills. Serve and return practice contributed to <13% of total practice time, with each skill predominately practised in isolation. Compared to the matchplay benchmark, players typically had less success (i.e., fewer serves/returns landing in the court), were less variable in shot selection and hit fewer serves to the extremities of the service box. As task representativeness increased fewer differences between practice and matchplay were observed. Tennis serve and return practice could be improved by better simulating specific competition affordances, providing greater opportunities to practice serve/return tactics and/or increasing the variability of practised skills.

Enhancing skill transfer in tennis using representative learning design.

Representative Learning Design advocates that practice should simulate the demands of competition. The effectiveness of increased task representativeness to improve serving skill of junior tennis players was assessed after a six-week intervention. Thirty-three participants (15.4 ± 1.9 years of age) were assigned to one of the three groups; "serve only" (participants served to no opponent), "serve return" (participants served to an opponent and hit no extra shots) or "serve +3rd" (participants served to an opponent and hit one extra shot). Using the validated representative practice assessment tool (RPAT) tasks were considered to be low, moderate and high in task representativeness, respectively. Participants hit 56 serves, twice weekly for 6-weeks. Pre and post serving performances were assessed via a skill test and in-situ matchplay using SportsCode and HawkEye ball tracking, respectively. Serve speed, landing locations, serve angle and positional advantage was obtained for 1st and 2nd serves. The relationship between increasing representativeness and increased skill acquisition was not linear, rather different behaviours emerged. For example, when hitting 2nd serves in matchplay, the low and moderate representative groups prioritised speed over placement while the high representative group prioritised placement over speed. Coaches therefore need to carefully individualise representativeness to an athletes' specific needs.

Sex Differences in Physical Fitness Characteristics and Match-Play Demands in Adolescent Netball: Should Male and Female Adolescents Co-compete in Netball?

Tissera, KM, Naughton, GA, Gabbett, TJ, Krause, LM, Moresi, MP, and Benson, AC. Sex differences in physical fitness characteristics and match-play demands in adolescent netball: Should male and female adolescents co-compete in netball? J Strength Cond Res 33(3): 846-856, 2019-Sports participation offers multifaceted benefits, especially during adolescence. However, policies relating to male and female adolescents co-competing in team sports can be prohibitive and lack an evidence base. This study aimed to strengthen evidence on coparticipation of male and female adolescents playing recreational netball. Off-court fitness characteristics (power, speed, agility, and high-speed intermittent running) and match-play performances from global positioning system (GPS) and video analysis were compared in adolescent males (n = 34, mean ± SD, age, 15.2 ± 0.8 years) and females (n = 45, mean ± SD, age, 14.9 ± 0.7 years), with previous recreational netball experience. Independent t-tests showed adolescent men outperforming females in all off-court fitness characteristics (p < 0.001). Two-way analyses of variance explored sex-based interactions in match-play (GPS accelerometer data and notational analyses) and type of competition (mixed-/single-sex formats) in forty-two 7-minute matches. Overall, no differences in match-play performances were found between males and females (p > 0.05). Notational skill-based comparisons showed that male skills were better in mixed- than single-sex matches. Conversely, competition format did not alter skills of females. Despite more netball experience in females and superior off-court fitness characteristics in males, on-court performance differences between males and females were minimal in these recreational adolescent netball players. Coparticipation in netball was not detrimental to the performance of either sex.

Equity of Physical Characteristics Between Adolescent Males and Females Participating in Single- or Mixed-Sex Sport.

Krause, LM, Naughton, GA, Benson, AC, and Tibbert, S. Equity of physical characteristics between adolescent males and females participating in single- or mixed-sex sport. J Strength Cond Res 32(5): 1415-1421, 2018-Policies on single- or mixed-sex junior sports participation continue to be challenged publically and legally. Often challenges relate to perceptions of size and performance variability between adolescent males and females, yet the evidence base behind these challenges lacks recent review and rigor. Physical performance was compared between males and females from 2 groups of younger (<13 years, n = 109, 67% females, 33% males) and older (≥13 years, n = 108, 43% females, 57% males) adolescents. Using a cross-sectional design, adolescents were tested for speed, strength, power, and endurance. No sex differences were found for most of the physical test results in the <13 years age group, although males showed greater endurance (p = 0.020) and upper-body strength (p = 0.010) than females. However, among adolescents aged ≥13 years, males scored better than females in all physical tests, without exception (p > 0.05). Further explorations comparing how many females in the same age grouping shared test results equal to or greater than the top third of males were fewer in the older than younger age group. Equality of participation in mixed-sex sport becomes more difficult to guarantee for older adolescents when results from generic sport-related physical test performances are considered.

Helping coaches apply the principles of representative learning design: validation of a tennis specific practice assessment tool.

Representative Learning Design (RLD) is a framework for assessing the degree to which experimental or practice tasks simulate key aspects of specific performance environments (i.e. competition). The key premise being that when practice replicates the performance environment, skills are more likely to transfer. In applied situations, however, there is currently no simple or quick method for coaches to assess the key concepts of RLD (e.g. during on-court tasks). The aim of this study was to develop a tool for coaches to efficiently assess practice task design in tennis. A consensus-based tool was developed using a 4-round Delphi process with 10 academic and 13 tennis-coaching experts. Expert consensus was reached for the inclusion of seven items, each consisting of two sub-questions related to (i) the task goal and (ii) the relevance of the task to competition performance. The Representative Practice Assessment Tool (RPAT) is proposed for use in assessing and enhancing practice task designs in tennis to increase the functional coupling between information and movement, and to maximise the potential for skill transfer to competition contexts.

Quantifying Contextual Interference and Its Effect on Skill Transfer in Skilled Youth Tennis Players.

The contextual interference effect is a well-established motor learning phenomenon. Most of the contextual interference effect literature has addressed simple skills, while less is known about the role of contextual interference in complex sport skill practice, particularly with respect to skilled performers. The purpose of this study was to assess contextual interference when practicing the tennis serve. Study 1 evaluated tennis serve practice of nine skilled youth tennis players using a novel statistical metric developed specifically to measure between-skill and within-skill variability as sources of contextual interference. This metric highlighted that skilled tennis players typically engaged in serve practice that featured low contextual interference. In Study 2, 16 skilled youth tennis players participated in 10 practice sessions that aimed to improve serving "down the T." Participants were stratified into a low contextual interference practice group (Low CI) and a moderate contextual interference practice group (Moderate CI). Pre- and post-tests were conducted 1 week before and 1 week after the practice period. Testing involved a skill test, which assessed serving performance in a closed setting, and a transfer test, which assessed serving performance in a match-play setting. No significant contextual interference differences were observed with respect to practice performance. However, analysis of pre- and post-test serve performance revealed significant Group × Time interactions. The Moderate CI group showed no change in serving performance (service displacement from the T) from pre- to post-test in the skill test, but did display improvements in the transfer test. Conversely, the Low CI group improved serving performance (service displacement from the T) in the skill test but not the transfer test. Results suggest that the typical contextual interference effect is less clear when practicing a complex motor skill, at least with the tennis serve skill evaluated here. We encourage researchers and applied sport scientists to use our statistical metric to measure contextual interference.

Understanding mismatches in body size, speed and power among adolescent rugby union players.

OBJECTIVES: With adolescent sport increasingly challenged by mismatches in size, new strategies are important to maximize participation. The objectives were to (1) improve the understanding of mismatches in physical size, speed and power in adolescent rugby union players, (2) explore associations between size and performance with demographic, playing-history, and injury profiles, and (3) explore the applicability of existing criteria for age/body mass-based dispensation (playing-down) strategies. DESIGN: Cross-sectional study. METHODS: Four hundred and eighty-five male community rugby union players were recruited from three Australian states selected to represent community-based U12, U13, U14 and U15 players. Body mass, stature, speed (10, 30, and 40 m sprints) and lower-leg power (relative peak power and relative peak force) were measured. Independent student t-tests, linear regressions and Chi square analyses were undertaken. RESULTS: Mean values in age groups for size, speed and power masked considerable overlap in the ranges within specific age groups of adolescent rugby players. Only a small proportion of players (approximately 5%) shared the highest and lowest tertiles for speed, relative peak power and body mass. Physical size was not related to injury. The mean body mass of current community rugby union players was above the 75th percentile on normative growth-charts. CONCLUSION: The notion that bigger, faster, and more powerful characteristics occur simultaneously in adolescent rugby players was not supported in the present study. Current practices in body mass-based criteria for playing down an age group lack a sufficient evidence for decision-making. Dispensation solely based on body mass may not address mismatch in junior rugby union.