Purpose: The aim of this study was to determine the effects of an 8-week program of resistance training (RT) or suspension training (ST) on explosive strength in prepubescent boys. Methods: Fifty-seven boys aged 10–11 years were assigned to 2 training groups, RT or ST or a control group (no training program). Boys trained twice weekly for 8 weeks. Results: A significant interaction was reported with a large (P < .001, ), medium (P < .001, ), and small effect sized (P ≤ .001, ) in the 1-kg ball throw, 3-kg ball throw, and time-at-20-m test, respectively. There was no significant interaction in the countermovement vertical jump or the standing long jump. Changes from preintervention to postintervention for the 1-kg ball throw were 5.94% and 5.82% for the ST and RT, respectively, and 8.82% and 8.14% in the 3-kg ball throw for the ST and RT, respectively. The improvement in the 20-m sprint was 1.19% for the ST and 2.33% for the RT. Conclusion: Traditional RT and ST seem to be effective methods for improving explosive strength in prepubescent boys. ST could be considered as an alternative modality to optimize explosive strength training in school-based programs.

Children aged 10–11 years pass through a dynamic developmental period marked by rapid changes in body size, shape, and composition, all of which are sexually dimorphic. The purpose of this study was to analyze the effects of gender on a school-based intervention in the prepubertal growth spurt. One hundred twenty-five healthy children (58 boys, 67 girls), fifth and sixth grade students from an urban public elementary school in Portugal (10.8 ± 0.4 years), were randomly assigned into two experimental groups: a strength training group (19 boys, 22 girls), and an endurance training group (21 boys, 24 girls); and a control group (18 boys, 21 girls; no training program). Training program for the two experimental groups was conducted twice a week for 8 weeks. Compared with the values at the beginning of the protocol, both strength and endurance training programs produced significant improvements (p< 0.05) in vertical and horizontal jumps, a 1 kg and 3 kg medicine ball throw, a 20 m sprint and VO2max, for both boys and girls. No significant changes were observed related to gender in training-induced strength (p> 0.05, η_p^2= 0.16, Power= 0.29) and aerobic (p> 0.05, η_p^2= 0.05, Power= 0.28) capacity. The results of the present study should be taken into consideration in order to optimize strength training school-based programs.

Suspension vs. plyometric training in children's explosive strength. J Strength Cond Res 36(2): 433-440, 2022-The aim of this study was to compare the effects of different training programs, that is, 8 weeks of suspension training (ST) or plyometric training (PT), on measures of strength and power in untrained healthy children. One hundred eighteen children (57 boys and 61 girls) aged 10-11 years (mean 6 SD: 10.84 6 0.46 years) were randomly assigned into PT (19 boys and 22 girls), ST (20 boys and 18 girls), and control (CT) (18 boys and 21 girls; no training program) group. Experimental groups were trained twice a week for 8 weeks. Countermovement jump, standing long jump, medicine ball throw, and 20-m sprint were measured at baseline and after intervention. The results showed a significant group effect on training-induced responses (F 5 10.26; p , 0.01; h 2 p 5 0.33), with clear improvements from pre-to posttraining in PT and ST. Regardless of training group, no differences were found in boys and girls (F 5 0.70; p 5 0.62; h 2 p 5 0.03). After 8 weeks of training, PT and ST showed increased performances in 1-kg (mean 6 CI 95%; 0.18 6 0.05 and 0.19 6 0.05 m) and 3-kg (0.12 6 0.08 and 0.12 6 0.09 m) medicine ball throws and 20-m sprints (20.08 6 0.03 s and 20.04 6 0.04 s) compared with CT (p , 0.05; d . 0.60). Standing long jump was significantly increased after ST when compared with CT (0.07 6 0.04 m; p , 0.01; d 5 0.88). Plyometric training showed higher improvements than ST in sprint (0.04 6 0.03; p 5 0.01; d 5 0.71). It is suggested that 8 weeks of ST or PT seems to be effective to improve strength-and power-related variables in healthy untrained children. These could be considered as alternatives to traditional resistance training and be applied in school-based programs.

<p>Nesta revisão foram analisados os estudos que apresentam resultados da resposta das hormonas consideradas de <em>stresse</em>, o cortisol e a testosterona, claramente associadas a um comportamento psicobiológico relacionado com a competição desportiva. Após uma pesquisa efetuada nas bases de dados <em>ScienceDirect e Medline/Pubmed</em>, foram selecionados sobre esta temática os estudos mais recentes realizados (&gt;2002). A maioria dos estudos recorre a amostras reduzidas e maioritariamente sobre o sexo masculino. O efeito antecipatório à competição, caracterizado por um aumento da ansiedade, geralmente determina um aumento da concentração de ambas as hormonas, em especial um aumento da concentração de cortisol. Estas alterações na resposta hormonal surgem igualmente associadas ao resultado da competição, com concentrações de testosterona mais elevada nos vitoriosos do que nos perdedores, juntamente com estados psicológicos positivos associados à vitória e negativos associados à derrota. O sexo e o nível desportivo do atleta são igualmente considerados fatores diferenciadores do comportamento hormonal em contexto competitivo. Estudos futuros deverão esclarecer os efeitos a longo prazo nessa resposta hormonal em atletas de elite, considerando o treino intenso prévio e a participação regular em competições de elevado nível. Fica também por aprofundar o efeito que determinada resposta hormonal terá no desempenho desportivo sobretudo quando considerada ao longo de um determinado evento competitivo ou torneio.</p>

This study aims to evaluate the relation between salivary concentrations of cortisol (C), testosterone (T), the ratio T:C and the individual performance of top-level female soccer athletes during official matches. Eighteen female athletes from a national soccer team (age 23.06 ± 4.33 years) participated in the study. Four official matches were analysed and the on-field time of each player as well as the index of individual effectiveness were calculated. Players were classified in two clusters according to their individual performance (cluster 1 – poor individual performance; cluster 2 – good individual performance) using K-means and their hormonal variables were compared. The players of cluster 2 generally revealed higher values (p˂.05) in both the positive actions and individual effectiveness, when compared with the players of cluster 1. The players of both clusters presented identical values of C, T and T:C at the four evaluated matches. The athletes of cluster 2 showed a significant increase in C (p˂.05) and a significant decrease in T and T:C before the games lost (M2 and M5). However, there was no linear relation between the variation of both hormones during the matches and the individual performance of players. Performance in competition revealed significant differences between players, though with no apparent relation to the hormonal kinetics of C and T before and after the matches.