School-Based TGfU Volleyball Intervention Improves Physical Fitness and Body Composition in Primary School Students: A Cluster-Randomized Trial.

This study aimed to explore whether a 16-week Teaching Games for Understanding (TGfU) volleyball intervention could improve primary school students' physical fitness and body composition. Eighty-eight primary school students (age 13.3 ± 0.3 years) were randomized to a TGfU volleyball intervention group (VG) or a control group (CG). The CG attended three regular physical education (PE) classes per week, while the VG attended two regular PE classes and a TGfU volleyball intervention that was implemented in the third PE class. Body composition components (body weight, body mass index, skinfold thickness, body fat percentage, and muscle mass percentage) and physical fitness (flexibility, vertical jumps (squat and countermovement jump-SJ/CMJ), 30 m sprint, agility, and cardiorespiratory fitness) assessments were performed pre-and post-intervention period. Significant interaction effects between VG and CG and pre- and post-test were found for the sum of five skinfolds (p < 0.0005, ŋp2 = 0.168), body fat % (p < 0.0005, ŋp2 = 0.200), muscle mass % (p < 0.0005, ŋp2 = 0.247), SJ (p = 0.002, ŋp2 = 0.103), CMJ (p = 0.001, ŋp2 = 0.120), 30 m sprint (p = 0.019, ŋp2 = 0.062), agility T-test (p < 0.0005, ŋp2 = 0.238), and VO2max (p < 0.0005, ŋp2 = 0.253). Further examination revealed a greater improvement among VG students compared to CG students in certain body composition and physical fitness outcomes. Implementing a TGfU volleyball intervention in the physical education curriculum appears to have effective stimuli for reducing adiposity and promoting physical fitness levels in seventh-grade primary school students.

School-Based Circuit Training Intervention Improves Local Muscular Endurance in Primary School Students: A Randomized Controlled Trial.

BACKGROUND: This study aimed to explore the effectiveness of a 12-week circuit training program in improving local muscular endurance in normal-weighted primary school students. METHODS: The study involved a parallel-group randomized trial with 606 primary school boys assigned to an experimental or a control group. The participants underwent a 12-week circuit training program that involved multi-joint, total-body workouts using body weight, resistance bands, and medicine ball exercises. The study measured the participants' local muscular endurance during sit-ups, dynamic trunk extensions on a Roman bench (DTE), and push-ups. RESULTS: After adjusting for the baseline, the treatment-grade interaction was significant for sit-ups (F = 7.74, p < 0.001, ηp2 = 0.04), DTE (F = 6.49, p < 0.001, ηp2 = 0.03), and push-ups (F = 9.22, p < 0.001, ηp2 = 0.05), where the experimental treatment was more beneficial than the control. The treatment effect seemed to vary depending on the individual's baseline local muscle endurance capacity. As the baseline local muscular endurance values increased, the treatment and grade effects became less beneficial. CONCLUSION: A 12-week circuit training program involving body weight, resistance bands, and medicine ball exercises suits school-based programs and can improve local muscular endurance in normal-weighted primary school boys. The experimental treatment was more effective than the control, and the individual baseline muscular endurance should be considered when designing training programs.

Multidimensional prediction approach in the assessment of male volleyball players' optimal body composition: the case of two elite European teams / Enfoque de predicción multidimensional en la evaluación de la composición corporal óptima de los jugadores de voleibol masculino: el caso de dos equipos europeos de élite

SUMMARY: This research aimed to create a multidimensional equation for predicting an optimal body composition model for elite-level European male volleyball players. The subject sample consisted of 36 elite volleyball players: national team members from two European countries - Slovenia and Serbia - in the 2017 season. Measurement of body composition was carried out using electrical multichannel bioimpedance (BIA - InBody 720), in which 11 variables were used (body height as a longitudinal one, and the other 10 as a system of body composition indicators). Based on the results of descriptive statistics, we can state that elite European male volleyball players are tall, heavy, and with nutritional status at the level of 198.5?6.5 cm, 92.3?5.9 kg and 23.44?1.44 kg•m-2, respectively. The percentage of body fat in the whole sample was 7.91?3.03 %, and the skeletal muscle mass index averaged 12.49?0.80 kg•m-2. For the evaluation and prediction of an optimal body composition model of elite male volleyball players, a multidimensional score (BC_Score) was defined, based on a simple, but sport-specific and playing position-sensitive model equation based on three dominant body characteristics of elite volleyball players: BH, PBF, and SMMI. In this manner, coaches can have a tool for managing the body composition status of players according to position, in terms of a deterministic, fully controlled system.

RESUMEN: Esta investigación tuvo como objetivo crear una ecuación multidimensional para predecir un modelo de composición corporal óptimo para los jugadores de voleibol masculinos europeos de élite. La muestra consistió en 36 jugadores de voleibol de élite, miembros del equipo nacional de dos países, Eslovenia y Serbia, en la temporada 2017. La composición corporal se realizó mediante bioimpedancia eléctrica multicanal (BIA - InBody 720), en la que se utilizaron 11 variables (la altura corporal como longitudinal y las otras 10 como sistema de indicadores de composición corporal). Con base en los resultados de las estadísticas descriptivas, observamos que los jugadores de voleibol de élite europeos son altos, pesados y con un estado nutricional de 198,5 ? 6,5 cm, 92,3 ? 5,9 kg y 23,44 ? 1,44 kg•m-2, respectivamente. El porcentaje de grasa corporal en toda la muestra fue de 7,91 ? 3,03 % y el índice de masa del músculo esquelético promedió 12,49 ? 0,80 kg•m-2. Para la evaluación y predicción de un modelo de composición corporal óptimo de jugadores de voleibol masculino de élite, se definió una puntuación multidimensional (BC_Score), basada en una ecuación de modelo simple, pero específica del deporte y sensible a la posición de juego, basada en tres características corporales dominantes de la élite. Jugadores de voleibol: BH, PBF y SMMI. De esta manera, los entrenadores pueden disponer de una herramienta para gestionar el estado de la composición corporal de los jugadores según la posición, en términos de un sistema determinista y totalmente controlado.