Sixteen men completed four trials at random as follows: (Trial A) performance of a single bout of resistance exercise preceded by placebo ingestion (vitamin C); (Trial B) ingestion of 1,500 mg L-arginine and 1,500 mg L-lysine, immediately followed by exercise as in Trial A; (Trial C) ingestion of amino acids as in Trial B and no exercise; (Trial D) placebo ingestion and no exercise. Growth hormone (GH) concentrations were higher at 30,60, and 90 min during the exercise trials (A and B) compared with the resting trials (C and D) (p < .05). No differences were noted in [GH] between the exercise trials. [GH] was significantly elevated during resting conditions 60 min after amino acid ingestion compared with the placebo trial. It was concluded that ingestion of 1,500 mg arginine and 1,500 mg ly sine immediately before resistance exercise does not alter exercise-induced changes in [GH] in young men. However, when the same amino acid mixture is ingested under basal conditions, the acute secretion of GH is increased.
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Richard R. Suminski, Robert J. Robertson, Fredric L. Goss, Silva Arslanian, Jie Kang, Sergio DaSilva, Alan C. Utter and Kenneth F. Metz
Ben D. Kern, Kim C. Graber, Amelia Mays Woods and Tom Templin
Physical education teachers have been criticized for not implementing progressive or innovative instruction resulting in enhanced student knowledge and skills for lifetime participation in physical activity. Purpose: To investigate how teachers with varying dispositions toward change perceive socializing agents and teaching context as barriers to or facilitators of making pedagogical change. Methods: Thirty-two teachers completed a survey of personal dispositions toward change and participated in in-depth interviews. Results: Teachers perceived that students’ response to instructional methods and student contact time (days/week), as well as interactions with teaching colleagues and administrators influenced their ability to make pedagogical changes. Teachers with limited student contact time reported scheduling as a barrier to change, whereas daily student contact was a facilitator. Change-disposed teachers were more likely to promote student learning and assume leadership roles. Conclusion: Reform efforts should include consideration of teacher dispositions and student contact time.
Alexandra Valencia-Peris, Joan Úbeda-Colomer, Jorge Lizandra, Carmen Peiró-Velert and José Devís-Devís
Background: Active gaming has emerged as a new option to foster physical activity in youth. The aim of this study was to estimate the prevalence of active gaming in adolescents, to determine differences between active and nonactive gamers by type of day, and to examine predictors of being an active gamer. Methods: A cross-sectional study was conducted with 3095 Spanish adolescents aged 12 to 18 years who self-reported their involvement in moderate to vigorous physical activity, sedentary behaviors, and active gaming. Those engaging in active gaming for at least 10 minutes per day were considered active gamers. Student’s 2-tailed t tests, chi-square test, and binomial logistic regression were performed. Results: About 25.9% of the adolescents were active gamers. They were younger, had higher body mass index, and spent more time on moderate to vigorous physical activity, television viewing, and sedentary video games with computer/console than nonactive gamers. There were more active gamers on weekends than on weekdays. On weekdays, more males than females were active gamers. Adolescents who did not meet sleep time guidelines were more likely to be active gamers on weekdays, whereas on weekends, being a girl, overweight/obese, and having a high socioeconomic status were predictors of being an active gamer. Conclusion: Because active gaming may contribute to meeting physical activity guidelines, the present findings could enable better targeting of physical activity promotion programs.
Giovani dos Santos Cunha and Gabriela Tomedi Leites
Kasper Salin, Mikko Huhtiniemi, Anthony Watt, Harto Hakonen and Timo Jaakkola
Background: This study examined the distribution of objectively measured physical activity (PA) and sedentary time of fifth-grade students during school, leisure time, and physical education (PE) classes. Demographic, anthropometric, and PA data were collected from 17 representative Finnish schools. Methods: To estimate the PA and sedentary time, participants (N = 592) wore wGT3X-BT ActiGraphs for 7 consecutive days. Comparisons were made between genders and different BMI groups. Results: From the study sample, 43.7% met the moderate to vigorous PA (MVPA) guidelines. Participants spent 62.2% of the day sedentary and 8.2% in moderate and vigorous activities. Boys performed more MVPA than girls, and girls were more sedentary during school days. Boys had more MVPA than girls in leisure time, but there were no differences in sedentary time. However, an examination of PA assessed during PE classes revealed no differences between boys and girls. Normal-weight boys engaged in more MVPA than overweight and obese boys. No differences were found for girls. Conclusions: The PE levels differ between different BMI groups in leisure time and during school but not during PE lessons. PA for overweight children should be targeted and compulsory PE time should be increased to achieve the PA guidelines.
Yuri Alberto Freire, Geovani de Araújo Dantas de Macêdo, Rodrigo Alberto Vieira Browne, Luiz Fernando Farias-Junior, Ágnes Denise de Lima Bezerra, Ana Paula Trussardi Fayh, José Cazuza de Farias Júnior, Kevin F. Boreskie, Todd A. Duhamel and Eduardo Caldas Costa
Background: This study analyzed the effect of walking breaks or low-volume high-intensity interval exercise (LV-HIIE) on markers of metabolic syndrome relative to a day of prolonged sitting. Methods: Twenty-five adults with excess body fat participated in this crossover trial: (1) 10-hour sitting day (SIT), (2) LV-HIIE followed by a sitting day (EX+SIT), and (3) sitting day with 5-minute walking breaks for every 20 minutes (SIT+WB). Glucose and blood pressure (BP) were measured before and 1 hour after 4 meals and 2 hours after lunch. Triglycerides were measured at baseline, 2, and 3.5 hours after lunch. Generalized mixed models were used to identify differences in the area under the curve (AUC) of BP and incremental AUC (iAUC) of glucose and triglycerides among the sessions. Results: iAUC-glucose was lower in SIT+WB than SIT (β = −35.3 mg/dL·10 h; 95% confidence interval, −52.5 to −8.2). AUC-diastolic BP was lower in SIT+WB than SIT (β = −14.1 mm Hg·10 h; 95% confidence interval, −26.5 to −1.6) and EX+SIT (β = −14.5 mm Hg·10 h; 95% confidence interval, −26.9 to −2.1). There were no differences in triglycerides and systolic BP levels among the sessions. Conclusion: Adults with excess body fat present lower glucose and diastolic BP during a day with breaks in sitting time compared with a prolonged sitting day with or without an LV-HIIE session.
Mehrez Hammami, Rodrigo Ramirez-Campillo, Nawel Gaamouri, Gaith Aloui, Roy J. Shephard and Mohamed Souhaiel Chelly
Purpose: To analyze the effects of a 9-week plyometric training program on the sprint times (5, 10, 20, and 30 m), change-of-direction speed (modified T test and modified Illinois test), jumping (squat jump, countermovement jump, countermovement jump with arms, and horizontal 5-jump test), upper-body strength (right and left handgrip, back extensor strength, and medicine ball throw), and balance (Y and stork balance tests) of female handball players. Methods: Athletes were randomly divided into experimental (n = 21; age = 13.5 [0.3] y) and control (n = 20; age = 13.3 [0.3] y) groups. Training exercises and matches were performed together, but the experimental group replaced a part of their normal regimen by biweekly upper- and lower-limb plyometric training. Results: Both groups improved performance, but to a greater extent in the experimental group compared with controls for 20- and 30-m sprint times (Δ% = 9.6, P < .05, d = 0.557 and Δ% = 20.9, P < .001, d = 1.07, respectively), change of direction (T test: P < .01, Δ% = 14.5, d = 0.993 and Illinois test: P < .01, Δ% = 7.9, d = 0.769), vertical and horizontal jumping (P < .05), all measures of upper-limb strength (P < .001), and left-leg stork balance (P < .001, Δ% = 49.9, d = 1.07). Conclusions: A plyometric training program allows female junior handball players to improve important components of their physical performance.
Sarah G. Sanders, Elizabeth Yakes Jimenez, Natalie H. Cole, Alena Kuhlemeier, Grace L. McCauley, M. Lee Van Horn and Alberta S. Kong
Background: Reports of physical activity (PA) measured via wrist-worn accelerometers in adolescents are limited. This study describes PA levels in adolescents at baseline of an obesity prevention and weight management trial. Methods: Adolescents (n = 930) at 8 high schools wore an accelerometer for 7 days, with average acceleration values of <50 mg, >150 mg, and >500 mg categorized as sedentary, moderate, and vigorous PA, respectively. In a 3-level mixed-effects generalized linear model, PA was regressed on sex, weight status, and day of week. Daily PA was nested within students, and students within schools, with random effects included for both. Results: Adolescents accumulated a median of 40 minutes daily of moderate to vigorous PA (MVPA). MVPA was significantly different for teens with obesity versus teens with normal weight (−5.4 min/d, P = .03); boys versus girls (16.3 min/d, P < .001); and Sundays versus midweek (−16.6 min/d, P < .001). Average sedentary time increased on weekends (Saturday: 19.1 min/d, P < .001; Sunday: 44.8 min, P < .001) relative to midweek but did not differ by sex or weight status. Conclusions: Interventions to increase PA in adolescents may benefit from focusing on increasing weekend PA and increasing MVPA in girls.
Sarah J. Wherry, Cheryl Der Ananian and Pamela D. Swan
Background: This study evaluated the feasibility and effectiveness of a home-based exercise intervention using the Wii Fit Plus®. Methods: A randomized, controlled trial of 24 women (age 53.6 [5.4] y) was used to assess compliance and changes in balance over 12 weeks. Balance was measured via the Berg Balance Scale and Frailty and Injuries: Cooperative Studies of Intervention Techniques-4 Scale at baseline and week 6 and week 12. Participant compliance to the intervention was captured via paper logs and the electronic record collected by the Wii Fit Plus®. Results: Participants in the intervention group were 95% compliant based on electronic records. There were no significant differences between groups for total score on either balance scale. There was a significant group × time interaction in favor of the intervention for maximum velocity y (P < .05), average velocity (P < .05), and was trending for maximum velocity x (P = .05) in the tandem step, eyes closed position. Conclusions: The results suggest that the Wii Fit Plus® is appropriate for home-based interventions in middle-aged women. Modest improvements in balance indicate that this may be an effective means to improve or maintain balance in older women. More research is needed to determine compliance and benefits to reducing fall risk in durations exceeding 12 weeks.