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Olfa Turki, Wissem Dhahbi, Johnny Padulo, Riadh Khalifa, Sana Ridène, Khaled Alamri, Mirjana Milić, Sabri Gueid and Karim Chamari

warm-up (NS) and a warm-up incorporating DS on subsequent COD performance (half T test) in young elite volleyball players. Methods Subjects A total of 16 players (age 16.88 [0.34] y, body mass 75.81 [5.41] kg, body height 1.91 [0.05] m, body mass index 20.84 [1.79] kg·m −2 , and body fat percentage 9

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João Ribeiro, Luís Teixeira, Rui Lemos, Anderson S. Teixeira, Vitor Moreira, Pedro Silva and Fábio Y. Nakamura

tolerated by injured or underrecovered athletes (eg, feeling delayed onset muscle soreness effects). 11 The aim of this study was to compare the effects of squat + hip-thrust training performed at OPL versus PT on jump, sprint, and COD performances measured in young elite-level soccer players. It was

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Javier Raya-González, Luis Suárez-Arrones, Archit Navandar, Carlos Balsalobre-Fernández and Eduardo Sáez de Villarreal

soccer career (established as 18.05 [6.69] y) in soccer players 4 has caused an annual increase in the number of injuries. 5 However, most epidemiological investigations have focused on professional 6 – 8 and semiprofessional senior soccer players, 9 with the studies on young soccer players being

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Daniel Gould, Charles Gene Wilson, Suzan Tuffey and Marc Lochbaum

This article examines psychological stress in children’s sports by presenting results from a panel discussion held with four young athletes ranging in age from 11 to 16 years. The discussion focused on stress and its sources, consequences, and how to cope. Results validated existing research on youth sports stress by showing that most young athletes are not placed under excessive stress. Rather, certain children in specific situations experience high levels of competitive state anxiety. Consistent with previous research, the stress of sports competition was also found to be no more anxiety provoking than other childhood evaluative activities. Future research directions identified from the panel’s responses included the need to identify strategies for coping with stress and ways of teaching these to young athletes, as well as ways to educate parents and coaches on how to improve communication skills. Finally, based on the panel’s remarks, practical implications for facilitating the youth sport experience are discussed.

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Stephen Langendorfer

Aquatic experiences including structured instructional programs for young children have become extremely popular over the past two decades despite opposition and controversy. Surprisingly, this popularity and controversy have not given rise to extensive or sustained research efforts by exercise scientists or aquatic professionals. Most information available for assessing risks and benefits of aquatic experiences for young children must be gleaned from ancillary sources in medical and educational literature. This paper reviews important issues and questions in the medical, developmental, and pedagogical areas of early childhood aquatics. The need for basic and applied research efforts by teams of exercise scientists from physiologic, psychologic, medical, and aquatic backgrounds is apparent.

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Dirk Pette and Dejan Škorjanc

We compared responses of the fast extensor digitorum longus (EDL) and tibialis anterior (TA) muscles in young (15-week) and aging (101-week) male Brown Norwegian rats to 50 days of chronic low-frequency stimulation (CLFS, 10 Hz, 10 hours/day). After 50 days of CLFS, the EDL muscles of the young (22-week) and aging (108-week) rats displayed similar increases in type IIA fibers, relative concentration of myosin heavy chain MHCIIa, elevations in mitochondrial citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities, and similar decreases in glycolytic enzyme activities (glyceraldehydephosphate dehydrogenase, lactate dehydrogenase). TA muscle in young rats contained a few cytochrome c oxidase negative (COX) type I fibers. Their number was ~2-fold elevated by CLFS. Conversely, aging muscle, which contained a slightly higher amount of COX fibers than young TA muscle, responded to CLFS with a significant decrease in COX− fibers. The appearance of small COX-positive type I fibers in stimulated aging muscle indicated that regenerating type I fibers “diluted” the COX-deficient fiber population.

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Peter S.W. Davies, Jian-Ying Feng, J. Anthony Crisp, Janice M.E. Day, Ann Laidlaw, Jidi Chen and Xiao-Peng Liu

The energy expenditure and hence energy requirements of 12 young Chinese gymnasts attending a specialized school in Beijing were assessed. Total energy expenditure was measured using the doubly labeled water technique and this, in conjunction with measures of basal metabolic rate (BMR), allows the calculation of a physical activity level (PAL). Mean PAL value for the gymnasts was 1.98, which is significantly different from published mean values found in nongymnast children of a similar age. This mean value is equivalent to very heavy levels of physical activity during the periods of training being undertaken. This is the first time that energy expenditure has been noninvasively measured in free-living young gymnasts. The data will be of use to sports scientists and nutritionists alike.

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Louise A. Kelly, John J. Reilly, Diane M. Jackson, Colette Montgomery, Stanley Grant and James Y. Paton

Tracking of total physical activity (PA), moderate to vigorous activity (MVPA), and sedentary behavior was assessed in 42 young children (mean age at baseline 3.8 years) over a 2-year period using the Actigraph accelerometer. Tracking was analyzed using Spearman rank correlations, percentage agreements, and kappa statistics. Spearman rank correlations were r = .35 (p = .002) for total PA, r = .37 (p = .002) for MVPA, and r = .35 (p = .002) for sedentary behavior. Percentage agreements for PA, MVPA, and sedentary behavior were 38, 41, and 26 respectively. Kappa statistics for PA, MVPA, and sedentary behavior ranged from poor to fair. Results suggest low levels of tracking of total physical activity, MVPA, and sedentary behavior in young Scottish children over a 2-year period.

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Thierry Long, Nathalie Pantaléon, Gérard Bruant and Fabienne d’Arripe-Longueville

Based on game reasoning theory (Shields & Bredemeier, 2001) and related research, the present study aimed at describing young elite athletes’ perceptions of rules compliance and transgression in competitive settings, as well as the underlying reasons for these actions. Semi-structured interviews were conducted with 10 young elite athletes. The qualitative analysis showed that respect and transgression of rules in competitive settings were perceived to depend upon the athletes’ individual characteristics (e.g., desire to win), their social environment (e.g., coach’s pressure, team norms), sports values and virtues (e.g., fair play, the effort ethic), and modern sports rewards (e.g., media recognition, financial rewards). These results confirmed and expanded game reasoning theory and illustrated moral disengagement mechanisms (Bandura et al., 1996) in the sport domain.

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Hans Braun, Karsten Koehler, Hans Geyer, Jens Kleinert, Joachim Mester and Wilhelm Schänzer

Little is known about the prevalence and motives of supplement use among elite young athletes who compete on national and international levels. Therefore, the current survey was performed to assess information regarding the past and present use of dietary supplements among 164 elite young athletes (16.6 ± 3.0 years of age). A 5-page questionnaire was designed to assess their past and present (last 4 weeks) use of vitamins, minerals, carbohydrate, protein, and fat supplements; sport drinks; and other ergogenic aids. Furthermore, information about motives, sources of advice, supplement sources, and supplement contamination was assessed. Eighty percent of all athletes reported using at least 1 supplement, and the prevalence of use was significantly higher in older athletes (p < .05). Among supplement users, minerals, vitamins, sport drinks, energy drinks, and carbohydrates were most frequently consumed. Only a minority of the athletes declared that they used protein/amino acids, creatine, or other ergogenic aids. Major motives for supplement use were health related, whereas performance enhancement and recommendations by others were less frequently reported. Supplements were mainly obtained from parents or by athletes themselves and were mostly purchased in pharmacies, supermarkets, and health-food stores. Among all athletes, only 36% were aware of the problem of supplement contamination. The survey shows that supplement use is common and widespread among German elite young athletes. This stands in strong contrast to recommendations by leading sport organizations against supplement use by underage athletes.