Objective: Strength training has gained recognition as an effective method to enhance physical fitness in children and adolescents. Its benefits include improvements in muscular strength, aerobic capacity (VO₂max), and motor performance. However, the diversity in training protocols and participant characteristics across studies necessitates a comprehensive synthesis of the evidence. The aim of this paper was to analyse the influence of a strength training programme in young people aged 6 to 16 years on different aspects of physical fitness. Methods: A search was carried out in the EBSCO, Web of Sciences, and Scopus databases. A total of 634 articles were reviewed, and 22 were finally included in the meta-analysis of articles published between 2013 and 2023 in English or Spanish. Twenty-two studies met the inclusion criteria and were assessed using the AXIS and PEDro tools. Standardised mean differences (SMD) and 95% confidence intervals (CI) were calculated. The variables that were most frequently repeated as criteria for evaluating the effectiveness of strength training were the following: (1) strength of the lower/upper body muscles; (2) VO₂max; (3) sprint performance. Results: Strength training interventions produced statistically significant improvements in all analysed variables. Most effective programmes lasted between 6 and 12 weeks, with 2–3 sessions per week. VO₂max showed the greatest improvement, followed by upper and lower limb strength, and sprint performance. Heterogeneity ranged from low to moderate. Conclusions: Supervised strength training programmes can significantly enhance physical fitness in school-aged children and adolescents. While the included studies varied in design and duration, measurable improvements were commonly observed in interventions lasting at least 6–8 weeks. Future research should explore age- and maturity-related responses through subgroup analyses. Limitations include the exclusion of studies published after 2023 and the wide age range of participants without biological stratification.

El objetivo fue determinar si la técnica de tiro libre ejecutada por jugadores de baloncesto de entre 9 y 11 años no participantes en ninguna selección autonómica y nacional coincidió con la técnica reportada por la literatura y estudios previos. El trabajo se realizó diferenciando la técnica de tiro antes de la salida y a la salida del balón. Participaron 12 jugadores varones de entre 9 y 11 años (M = 10,43, DT = ,63) que nunca habían participado en ninguna selección autonómica ni nacional. Se utilizó la metodología observacional a través de un diseño puntual/nomotético/multidimensional. Se grabó a los jugadores realizando un test que constaba de 10 tiros libres. Posteriormente, dos observadores observaron la ejecución técnica de cada uno de los tiros realizados por los jugadores. Se realizó la detección de t-patterns mediante el software Theme v.6 EDU. No se detectó ningún t-pattern antes de la salida del balón ni a la salida debido a que los tiros se realizaron siguiendo conductas muy dispares, que no se repitieron de forma regular en el tiempo. En el presente trabajo se utilizó un instrumento de observación que permitió la obtención de información directamente aplicable a la realidad diferenciando lo que ocurre antes de la salida del balón y a la salida del mismo. Se comprobó que los jugadores analizados, los cuales no jugaban en ninguna selección, ejecutaron una técnica de tiro que contrastaba en varios criterios con las recomendaciones propuestas por la literatura y estudios previos. The purpose was to determine whether the free throw technique of under-12 basketball players, who did not participated in any regional and national team, was similar to the technique reported by the literature and previous studies. The analysis differentiated prior to shoot and at ball release moments. Participant were 12 male players between 9 and 11 years old (M = 10.43, SD =, 63) who had never participated in any regional and national team. The observational methodology was used through a point/nomothetic/multidimensional design. The players were recorded performing a test consisting of 10 free throws. Two observers observed the technical execution of each of the shots made by the players. T-patterns were detected using Theme v.6 EDU software. Neither prior to ball release nor at ball release t-patterns were detected because the free throws followed very different behaviours, which were not repeated regularly over time. In the present work, an observation instrument was used that allowed obtaining information directly applicable to reality, differentiating between the free throw technique prior to shoot and at ball release moments. The analysed players, who did not play in any regional and national team, executed a free throw technique that contrasted in several criteria with the literature and previous studies recommendations. O objetivo foi determinar se a técnica do tiro livre executada por jogadores de basquete entre 9 e 11 anos de idade que não participavam de nenhuma seleção regional e nacional coincidia com a técnica relatada na literatura e em estudos anteriores. O trabalho foi realizado diferenciando a técnica do chute antes do início e do início da bola. Participaram 12 jogadores do sexo masculino entre 9 e 11 anos (M = 10,43, DT =, 63) que nunca haviam participado de nenhuma equipe regional ou nacional. A metodologia observacional foi utilizada através de um desenho pontual/nomotético/multidimensional. Os jogadores foram gravados realizando um teste composto por 10 chutes da linha de lance livre. Posteriormente, dois observadores observaram a execução técnica de cada um dos tiros feitos pelos jogadores. Os t-patterns foram detectados usando o software Theme v.6 EDU. Nenhum t-patterns foi detectado antes do início da bola ou no início, porque os chutes foram feitos seguindo comportamentos muito diferentes, que não foram repetidos regularmente ao longo do tempo. No presente trabalho, foi utilizado um instrumento de observação que permitiu obter informações diretamente aplicáveis à realidade, diferenciando o que ocorre antes da saída da bola e da saída da bola. Verificou-se que os jogadores analisados, que não jogaram em nenhuma seleção, executaram uma técnica de chute que contrasta em vários critérios com as recomendações propostas pela literatura e estudos anteriores.