ABSTRACT
Junior tennis players travel a lot to play tennis tournaments; this causes them to spend a lot of time away from their homes and disrupts their training, which could reduce their performance and increase the risk of injury. The purpose of this study was to analyze the changes in physical performance and body composition after a six-week international tour in young Chilean female tennis players. Thirty young female tennis players (15.4 ± 0.6) participated in this study. Body weight, skinfolds, and perimeters were measured. Body fat percentage (BFP) and skeletal muscle mass (SMM) were calculated. For physical performance, 5 m sprint, the 505 with stationary start test (505 test), the pro-agility test, countermovement jump (CMJ), and medicine ball throw (MBT) were evaluated. The results show a significant increase in BFP and decrease in SMM (p < 0.01; d = -0.18 and 0.19, respectively). In terms of physical performance, 5 m sprint, the 505 test (p < 0.01; d = -0.95 and -0.95, respectively), CMJ, MBT, and HJ significantly decreased post-tour (p < 0.05; d = 0.96, 0.89 and 0.47, respectively). We conclude that, after a six-week international tour, there were changes in body composition and a significant decrease in 5 m sprint, the 505 test, CMJ, and MBT.
ABSTRACT
PURPOSE: The aim of this study was to evaluate the performance of healthy Chilean children aged 3-10 years in the 6-minute walking test (6MWT) and cardiometabolic risk variables and to determine sex- and age-specific reference values. METHODS: This study involved 1165 healthy children (age = 6.36 [1.70] y old). The 6MWT was used to evaluate exercise performance. Furthermore, anthropometric measures were collected, like weight, height, body mass index, waist circumference, and skin folds. Resting heart rate and blood pressure (BP) were also evaluated. RESULTS: The prevalence of overweight and obesity was 35.0% and 25.4% in preschoolers and 29.0% and 36.2% in school-age children, respectively, showing significant differences (P < .05) between age groups. The distance walked (6-min walk distance) increased significantly year on year at ages from 3 to 10 years. According to the regression analysis, 6MWT performance was positively related to age, systolic BP, and height, whereas it was negatively related to ∑4 skinfold fat, resting heart rate, diastolic BP, and waist circumference. CONCLUSIONS: This study provides a reference equation and an age- and sex-adjusted percentile curve to assess the predicted 6MWT performance in a cohort of prepubertal Chilean children. The 6-minute walk distance depends mainly on age; however, other variables, such as resting heart rate, BP, skinfold fat, and waist circumference, add significant information and should be taken into account.
ABSTRACT
Abstract Introduction: The hip muscles play an important role in controlling the transverse and frontal plane of the femur during displacement. The hip extension and abduction/adduction exercises are among the most widely evaluated protocols both clinically and in research. Objective: To compare which assessment protocol in an isokinetic strength regime (distal grip-ankle vs. proximal grip-knee) best represents the action of hip extension and to analyze the test-retest reliability in the variables peak force (PF) and work (W). Methods: A total of 20 subjects participated in this research. All participants were female. The mean and standard deviations of age, weight and height were 21 ± 3.9 years, 65 ± 11 kg, 166 ± 3.4 cm, respectively. Results: Significant differences were found in both variables (PF and W) between protocols 1 and 2 (p < 0.05) on assessment days 1 and 2. No differences between days 1 and day 2 in either protocol (p < 0.05) were found. Index values of interclass correlation (ICC) of protocol 1 ranged between 0.38 and 0.86. In protocol 2 the ICC range was between 0.33 and 0.87. Conclusions: In light of these results, the hip extension exercise with a proximal grip best represents the strength of the muscle groups involved in this action.
Resumo Introdução: Os músculos do quadril desempenham um papel importante no controle do plano transverso e frontal do fêmur durante o deslocamento. Os exercícios de extensão e abdução/adução do quadril estão entre os protocolos mais amplamente avaliados tanto na clínica como na pesquisa. Objetivo: Comparar qual protocolo de avaliação em um regime de força isocinética (aperto distal no tornozelo versus aperto proximal no joelho) melhor representa a ação de extensão de quadril e analisar a confiabilidade teste-reteste nas variáveis de força máxima de (FM) e trabalho (T). Métodos: Um total de 20 indivíduos participou desta pesquisa. Todos os participantes eram do sexo feminino. A média e desvios-padrão de idade, peso e altura foram 21 ± 3.9 anos, 65± 11 kg e 166 ± 3.4 cm, respectivamente. Resultados: Foram encontradas diferenças significativas em ambas as variáveis (FM e T) entre protocolos 1 e 2 (p < 0,05) nos dias 1 e 2 de avaliação. Não houve diferenças entre os dias 1 e dia 2 em qualquer protocolo (p < 0,05). O índice de valores de correlação interclasse (ICC) do protocolo 1 variou entre 0,38 e 0.86. No protocolo 2 a faixa do ICC foi entre 0,33 e 0,87. Conclusões: Tendo em conta estes resultados, o exercício de extensão de quadril com uma fixação proximal é quem melhor representa a força dos grupos musculares envolvidos nesta ação.
