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 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.

Relación entre Edad y Criterios de Rendimiento y Participación en Jugadores de Baloncesto de Alto Rendimiento / Relationship between Age and Performance and Participation in High Performance Basketball Players / Relação entre idade e desempenho e participação em jogadores de basquetebol de alto desempenho

El objetivo del presente estudio fue analizar la edad a la que los jugadores de baloncesto de alto rendimiento obtienen los mejores valores de participación y de rendimiento deportivo. Para ello se analizaron el total de jugadores de la liga ACB de baloncesto participantes en la liga regular desde la temporada 2005-2006 hasta la temporada 2017-2018 con el requisito de haber disputado un mínimo de 5 minutos en al menos 5 partidos (n = 2973). Se dividió a la muestra total en cuatro grupos de edad: a) hasta 25 años, b) 25.1 y 28 años, c) de 28.1 a 31 años, y d) mayores de 31 años. De cada uno de los jugadores se registraron los datos estadísticos que fueron clasificados en dos grupos: a) variables relacionadas con la participación, y b) con el rendimiento. Los resultados indican que, en la participación, son los menores de 25 años los que destacan por ser el único rango de edad por debajo de la media general; mientras que, desde la perspectiva del rendimiento, son los jugadores más veteranos los que obtuvieron mejores resultados

The objective of the present study was to analyse the age at which high performance basketball players obtain the best values of participation and sports performance. Total number of players in the ACB basketball league participating in the regular season was analysed from the 2005-2006 season until the 2017-2018 season with the requirement of having played a minimum of 5 minutes in at least 5 matches (n = 2973). The total sample was divided into four age groups: a) up to 25 years, b) 25.1 and 28 years, c) from 28.1 to 31 years, and d) over 31 years. Statistical data were recorded from each of the players and classified into two groups: a) variables related to participation, and b) performance. The results indicate that, in the participation, it is the under-25s who stand out as the only age range below the general average; whereas, from the perspective of performance, it is the oldest players who obtained the best results

O objetivo do presente estudo foi analisar a idade em que jogadores de basquetebol de alto rendimento obtêm os melhores valores de participação e desempenho esportivo. Para este fim, o número total de jogadores de basquete da ACB que participam da liga regular da temporada 2005-2006 até a temporada 2017-2018 foi analisado com a exigência de ter jogado um mínimo de 5 minutos em pelo menos 5 partidas (n = 2973). A amostra total foi dividida em quatro grupos etários: a) até 25 anos, b) 25,1 e 28 anos, c) de 28,1 a 31 anos ed) com mais de 31 anos. Dados estatísticos foram registrados de cada um dos jogadores, os quais foram classificados em dois grupos: a) variáveis relacionadas à participação eb) desempenho. Os resultados indicam que, na participação, são os menores de 25 anos que se destacam como a única faixa etária abaixo da média geral; enquanto, do ponto de vista do desempenho, os jogadores mais veteranos obtiveram os melhores resultados