Effect of Rule Modifications on Kinematic Parameters Using Maturity Stage as a Moderating Variable in U-10 Football Players.

The aim of the present study was to analyse the effects of regulatory modifications in competitive situations on cinematic variables, considering maturity stage as a moderating factor, in youth football players. A quasi-experimental study was conducted in which 45 players with a mean age of 9.47 ± 0.54 participated. The independent variable analysed was the modification of rules (playing time, scoring, and specific rules). The dependent variables analysed were cinematic variables. These variables were recorded with WimuTM. The maturity stage was considered a moderating factor in this effect. The main results indicate that the modified competition reduced the total distance covered, maximum acceleration speed, and distance covered in acceleration and deceleration in different speed zones. In addition, the maturity stage was found to moderate the effect of the intervention on the total distance covered, distance covered by accelerating in zone 3, and distance covered by decelerating in zone 3. Thus, the proposed modification appeared to reduce the physical demand for competition. Furthermore, it reduced the differences between players with early maturational development and those with late maturational development.

Perceived self-efficacy by Under-10 tennis players when scaling the equipment and play area.

The modification of child-sports aims to develop an optimal learning environment that facilitates the emergence of desirable psychological outcomes (e.g., self-efficacy). The aim of the study was to assess the effect of reducing net height and court size on self-efficacy and shot-efficacy of U-10 tennis players in a real-game context. Twenty U-10 tennis players (M = 9.46, SD = 0.66 years of age; M = 3.65, SD = 1.53 years of tennis experience) played two round-robin tournaments one week apart in the same order and schedule. The first tournament was played under the International Tennis Federation's Tennis 10s regulation at green stage (GT). Afterwards, the modified tournament (MT) was played with the same regulation GT, however, net height (0.91 m-0.80 m) and court size (23.77 m × 8.23 m-18.00 m × 8.23 m) were reduced. Results accomplished using Bayesian and Frequentist inferences showed an increase in players' self-efficacy when serving in MT than GT (BF10 = 4.796; δ = -0.576; and p = .011). This is increase may be due to a reduction in their serving faults in MT (BF10 = 6.169; δ = -0.591; and p = .010). Therefore, reducing net height and court size enhances the serve performance and self-efficacy and thus promotes positive tennis experiences.

Influence of Rule Manipulation on Technical-Tactical Actions in Young Basketball Players: A Scoping Review.

The purpose of this scoping review was to analyse the effect of rules modification on technical and tactical action in young basketball. The publications search period ranged from January 2007 to December 2021. The search covered the following electronic databases: SCOPUS, SportDiscus, and the Web of Science core collection. Following this search process, 18 articles were included in the review. The following variables were analysed: characteristics of the sample, the constraints manipulated, the duration of the intervention, and the effect on technical-tactical actions. The studies reviewed modified the following constraints: (a) number of players (66.7%), (b) court dimensions (27.8%), (c) ball/player interactions (11.1%), and (d) ball/player interactions, basket height, game time and number of baskets (5.6%, respectively). The findings show that rule manipulation can increase players' participation and promote the variability of players' actions. The current evidence about rule modification in youth basketball presents areas in which more studies are needed to have a complete perspective of their impact in practice and competition through the different stages of players' development. Taking into account individual needs and developmental stages, further studies should consider different age groups (e.g., from U-10 to zU-14) and female players. Expanding scientific knowledge in this area would help coaches make short- and long-term plans in accordance with players' developmental stages.

Effect of scaling basket height for young basketball players during the competition: seeking out positive sport experiences.

Proper scaling of sports equipment is necessary to ensure an optimal teaching-learning process . This study aimed to analyse the effect of reducing basket height on the technical-tactical actions, physical participation, self-efficacy, cooperation and enjoyment of young basketball players in the competition. 51 under-14 male basketball players from four teams were chosen as the sample. The data collection included 2,286 attack phases during 12 matches. All players competed in two tournaments using official basketball rules but different basket heights (official basket height, 3.05 metres, and modified basket height, 2.80 metres). The dependent variables were: a) types of shooting actions, shot efficacy, and shooting conditions; b) the duration, type, number of passes done, and efficacy of the attack phases; c) heart rate values; and d) perception of specific and physical self-efficacy, collective efficacy, cooperation, and enjoyment. The results show that the scaled basket promoted game styles that increased the occurrence of fast-breaks and long positional attack phase. Shot efficacy for all shot types improved (not-significantly) and brought change in players' specific self-efficacy and enjoyment. These findings show that scaling equipment can help the transition from mini-basket to regular basket (under-14 age group) by generating better conditions for players' development.

Does Youth Soccer Players' Group Cooperation Improve when Pitch, Goal, and Team Size are Reduced?

The aim of this study was to analyse the effects of the modification of the pitch size, goal size, and the number of players per team on the level of cooperation in youth soccer players (U-12). A quasi-experimental design was implemented to measure the effects of the changes in the number of players per team (8-a-side vs. 5-a-side), goal size (6 x 2 m vs. 3 x 2 m), and field size (58 x 38 m vs. 38 x 20 m) on the cooperation. Four soccer teams under-12 (n = 48 players) participated in three tournaments (standard rules; proposed rules; standard rules). The five variables of cooperation were measured using the "Sports Cooperation Questionnaire": conditional cooperation, cooperation with the coach, disposition of unconditional cooperation, situational cooperation with teammates, and situational cooperation outside the field of play. Players presented the same level of cooperation in conditional cooperation, situational cooperation with teammates, and situational cooperation outside the field of play with both types of rules. The modification of rules involved a reduction of the cooperation with the coach and a disposition of unconditional cooperation. The causes of the reduction may be related to players' adaptation to new tactical dispositions and game situations. Future studies are needed of player's cooperation and different competition rules in youth sports.

Design, Validation, and Reliability of an Observational Instrument for Technical and Tactical Actions in Singles Badminton.

Technical and tactical actions are decisive in terms of badminton player competitive performance. The main objective of this research was to design, validate, and estimate the reliability of an observational instrument for the analysis of the tactical and technical actions in individual badminton. The process was carried out in four different steps: first, there was a review of the scientific literature and a preliminary list of variables was made; second, a qualitative and quantitative assessment was completed by 10 badminton expert judges; in the third step, the content validity was estimated using Aiken's V coefficient; finally, intra-observer reliability and interobserver reliability were tested by two observers specialized in badminton using the Cohen's Kappa coefficient and the intraclass correlation coefficient. Strokes were used as the unit of measure by our observational instrument; every time badminton players hit the shuttlecock, 22 variables (eight contextual variables, seven variables related to the result of the match, and seven variables related to the game) are observed. The minimum Aiken's value was 0.58, and reliability was 0.63. In spite of these values, none of the variables had to be removed, but there were modifications in terms of drafting in some of them. The main findings confirmed the validity and the usefulness of this instrument.

Effect of Scaling Task Constraints on the Learning Processes of Under-11 Badminton Players during Match-Play.

Scaling equipment and the playing space according to junior badminton players' characteristics and needs is a key aspect to design optimal learning environments. The purpose of the study is to analyze the incidence of reducing the court size (from 13.40 m × 5.18 m to 11.88 m × 5.18 m) and net height (from 1.55 m to 1.30 m) for under-11 badminton players on the following technical and tactical variables: (a) service area; (b) stroke effectiveness; (c) kinds of technical strokes; (d) players' hitting area; (e) shuttle landing area; (f) shuttle flight; and (g) rally length. Twenty-eight badminton players (mean age of players: 9.81 ± 0.93) were selected and played a badminton competition (B) with the current federative rules and a mini-badminton competition (MB) with the altered net height and court dimensions. The results showed that a lower net height and a shorter court would increase the frequency and variability of strokes and play patterns, introducing quantifiable changes considered beneficial for children in their first stages, both in training and competition.

Changes in Markers of Oxidative Stress and α-Amylase in Saliva of Children Associated with a Tennis Competition.

The purpose of this paper was to analyze the changes caused by a one-day tennis tournament in biomarkers of oxidative stress and α-amylase in saliva in children. The sample was 20 male active children with the following characteristics: (a) age of players = 9.46 ± 0.66 years; (b) weight = 34.8 ± 6.5 kg; (c) height = 136.0 ± 7.9 cm; (d) mean weekly training tennis = 2.9 ± 1.0 h. The tennis competition ran for one day, with four matches for each player. Data were taken from the average duration per match and the rating of perceived exertion (RPE). Four biomarkers of antioxidant status: uric acid (AU), Trolox equivalent antioxidant capacity (TEAC), ferric reducing ability of saliva (FRAS, cupric reducing antioxidant capacity (CUPRAC) and salivary alpha-amylase (sAA) as a biomarker of psychological stress were measured in saliva. The time points were baseline (at home before the tournament), pre-competition (immediately before the first match) and post-match (after each match) measurements. The four biomarkers of antioxidant status showed a similar dynamic with lower values at baseline and a progressive increase during the four matches. Overall one-day tennis competition in children showed a tendency to increase antioxidant biomarkers in saliva. In addition, there was an increase in pre-competition sAA possibly associated with psychological stress. Further studies about the possible physiological implications of these findings should be performed in the future.

Using Smart Sensors to Monitor Physical Activity and Technical-Tactical Actions in Junior Tennis Players.

The use of smart devices to obtain real-time data has notably increased in the context of training. These technological tools provide data which monitor the external load and technical-tactical actions related to psychological and physical health in junior tennis players. The purpose of this paper is to monitor technical-tactical actions and physical activity during a current tennis competition in the Green stage using a Zepp Tennis Smart Sensor 2. The participants were 20 junior tennis players (under 10 years of age), with an average age of 9.46 years. The total number of strokes (n= 21,477) during 75 matches was analyzed. The study variables were the following aspects: (a) number of strokes, (b) ball impact in the sweet spot; (c) racket speed; (d) ball spin; (e) calories burned; and (f) match time. The current system of competition, based on knockout, does not meet the World Health Organization's recommendations for daily physical activity time. Players mainly used flat forehands with a lack of variability in technical-tactical actions which did not meet the current learning opportunity criteria of comprehensive methodologies. The competition system in under-11 tennis should be adapted to the players' characteristics by improving the variability and quantity of practice.

Effect of the Modification of the Number of Players, the Size of the Goal, and the Size of the Field in Competition on the Play Actions in U-12 Male Football.

A player's sports development involves a long process. The modification of rules for youth players seeks to adapt the sport to the child and his/her development. The manipulation of rules affects the technical and tactical skills demonstrated by players and, therefore, their development. The objective of this study was to analyse the effect of a reduction in the number of players (from 8 per team to 5 per team), the size of the goal (from 6 × 2 m to 3 × 2 m) and the playing space (from 58 × 38 m to 38 × 20 m), on the technical and tactical actions in youth football players. A quasi-experimental A-B-A design was implemented to assess the effect of the rule changes. The players (n = 40) played three tournaments using two competition formats (official rules, modified rules, and official rules). The results show that the use of the modified rules generated a greater number and variability in the technical-tactical actions, a greater number of actions with teammates in the pass line, a greater continuity in the game, a greater number of attack and defence actions in areas close to the goal, and favours team play. The experimental format fits the players' individual progression better (U-12) as well as the players' and teams' collective development, and it will allow players to evolve from the individual development of previous stages.

Design, Validation, and Reliability of an Observation Instrument for Technical and Tactical Actions of the Offense Phase in Soccer.

The use of observational methodology in the sports context provides coaches and other sports professionals with flexible tools that adapt to their needs. In collective sports, the use of these instruments is common for the technical and tactical analysis of the game. Based on the importance of data quality in these instruments, the purpose was to design, validate, and test the reliability of a mixed observational instrument of field formats and category systems to analyze technical and tactical actions in the offense phase in soccer. The instrument collects information regarding the actions with the ball, moment of the play (start, development, and end), and contextual situation for the offensive team and for the goalkeeper. The instrument design, validation, and reliability calculation were done in four stages: (a) review of the literature, (b) design the first draft of the instrument, (c) experts' qualitative and quantitative review of the instrument, and (d) observer training test (reliability calculation). The content validity was established by 12 experts (Ph.D. in sports science or soccer coach with at least of 10 years of coaching experience). The Delphi methodology was used. Experts did a quantitative (scale 0-10) and qualitative evaluation. Experts were asked about: (a) comprehension of the criteria, categorical cores, degree of openness, and their definitions, (b) pertinence of categorical cores and degree of openness, and (c) whether to include other categorical cores or degree of openness in the observation instrument. The lowest Aiken's V index was 0.91 for the categorical core "numerical situation with opponent goalkeeper." The inter- and intra-observer reliability presented good levels of agreement. The lowest Kappa index was 0.96 for the inter-reliability in the categorical core "defensive pressing lines" and was 0.98 for the intra-reliability in the categorical core "ball height (start of ball possession)," "distance of the defensive player," "ball height (end of ball possession)," "numerical situation," and "defensive pressing lines." The coefficients of the generalizability analysis showed a high level of accuracy, validity and reliability of the instrument. The results show that the instrument allows to obtain objective, valid and reliable information about the offensive phase in soccer.

Effect of Modification Rules in Competition on Technical-Tactical Action in Young Tennis Players (Under-10).

Adapting competitions to young players' characteristics is an important pillar in the optimal teaching-learning process. The objective of the present study is to analyze the effect of modifying net height (from 0.91 to 0.80 m) and court dimensions (from 23.77 × 8.23 m to 18 × 8.23 m) for under-10 (U-10) tennis players on the following: (a) kinds of technical and tactical basic, situational, and special strokes; (b) tennis players' hitting area; (c) landing location of the serve; (d) ball landing location after the serve; (d) stroke effectiveness; and (e) rally length. The study design was quasi-experimental in nature, observing the fluctuation/change in technical-tactical variables of the tennis players when playing a "Tennis 10s Green Competition" (GC) with the current federative rules and a redesigned competition "Modified Competition" (MC) including altered net height and court dimensions based on small-sided games (SSGs) and equipment scaling. Twenty U-10 tennis players were studied (age of players = 9.46 ± 0.66 years, average weekly training in tennis = 2.90 ± 1.07 h, years of experience = 3.65 ± 1.53 years). The results showed that in MC, there was a greater technical-tactical variability compared with the GC in terms of the following: (a) greater service effectiveness; (b) more situational and special strokes; and (c) a more equitable change in the distribution of hitting and ball landing locations. The values of MC showed that the current adaptation rules and equipment in federated U-10 competitions might not be enough to improve the teaching-learning process under the comprehensive approach. The current competition for U-10 tennis players (stage green) should be redesigned, in order to build an optimal process of affordances to develop a multidimensional positive impact during this training stage.

Design and Validation of an Observational Instrument for the Technical-Tactical Actions in Singles Tennis.

The competitive performance in tennis practice is determined by the effectiveness of technical tactical action. The main objective of the present study was to design and validate an observational instrument with the aim of analysing the technical-tactical in singles tennis. The instrument uses the stroke as a unit of measure, so that each time a player hits a ball, a total of 23 variables are analyzed. The variables collect information about: (a) matching context; (b) result; and (c) technical-tactical information of the stroke (five variables: sequences of the stroke of the point, kind of technical and tactical stroke, bounce area, hitting, and effectiveness area). The design and validation of the instrument consisted on five different stages: (a) review of the scientific literature and variables definition by experts, (b) pilot observation study, (c) qualitative and quantitative assessment of the instrument by experts, (d) review and confirmation of the instrument by experts (content validity), and (e) observation training and reliability evaluation. From 23 expert judges, divided into three panels, and four observers the instrument went from being composed of 38 variables (eight contextual, seven related to the result and 23 related to the game) to 23 (eight contextual variables, 10 of result and five of game), with minimum Aikens's V values of 0.94 and reliability of 0.81. The results show that the designed instrument allows obtaining valid and objective information about the technical-tactical actions of the players and their performance in singles tennis.

Incidencia de la modificación de reglas y sistema de competición sobre los niveles de satisfacción en jugadores de baloncesto under 14 / Effect of rules modification and competition system on levels of satisfaction in basketball players under 14

El objetivo del presente estudio fue analizar la opinión y la satisfacción de los jugadores de baloncesto tras la aplicación de un torneo en el que se modifican y adaptan tanto el reglamento como el sistema de competición. Se realizaron entrevistas semi-estructuradas a 44 jugadores de categoría infantil (under-14) masculino. A partir de un análisis cuantitativo y cualitativo de los datos se obtuvieron los siguientes resultados: a) Los jugadores respondieron antes del torneo que las reglas que conforman el reglamento actual son relativamente adecuadas, señalando como reglas a modificar las relacionadas con el incremento del tiempo de juego y de la eficacia en el lanzamiento; b) tras la aplicación del nuevo torneo, los jugadores señalan elevados niveles de satisfacción con las nuevas reglas, especialmente las relacionadas con el incremento de la participación y de la eficacia en el lanzamiento (altura de la canasta, la posibilidad de jugar situaciones de 4x4 y de 1x1); c) a pesar de mostrarse especialmente satisfechos con la estructura del nuevo torneo, la mayoría de ellos prefieren un torneo normal (5x5), aunque las razones expresadas no se basan en aspectos exclusivamente deportivos, sino organizativos (AU)

The objective of the present study was to analyze the opinion and satisfaction of the basketball players after the application of a tournament in which both the rules and the competition system are modified and adapted. Semi-structured interviews were conducted with 44 male and female players (under-14). From a quantitative and qualitative analysis of the data, the following results were obtained: a) The players responded before the tournament that the rules that conform the current regulation are relatively adequate, indicating as rules to modify those related to the increase of the time of Play and effectiveness at launch; B) Following the implementation of the new tournament, players indicate high levels of satisfaction with the new rules, especially those related to increased participation and efficiency at launch (basket height, the possibility of playing 4x4 situations And 1x1); C) Despite being especially pleased with the structure of the new tournament, most of them prefer a normal tournament (5x5). The reasons given are not based on exclusively sporting aspects, if not on organizational aspects (AU)