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.
Richard R. Suminski, Robert J. Robertson, Fredric L. Goss, Silva Arslanian, Jie Kang, Sergio DaSilva, Alan C. Utter and Kenneth F. Metz
Bruno P. Melo, Débora A. Guariglia, Rafael E. Pedro, Dennis A. Bertolini, Solange de Paula Ramos, Sidney B. Peres and Solange M. Franzói de Moraes
Background: Combined exercise (CE) has been recommended for individuals living with HIV/AIDS (ILWHA) under antiretroviral therapy. However, depending on the intensity and duration, physical exercise may occasionally increase inflammatory parameters and reduce immunological responses that if not reversed, cause health injury specifically in this population. Information about immunological and hormonal responses after CE in ILWHA has not been completely elucidated. Therefore, the aim is to verify the acute effects of CE on cortisol, testosterone, immunoglobulin A, and pro-inflammatory and anti-inflammatory cytokines over 24 hours in ILWHA. Methods: Noninfected individuals and ILWHA undergone 5 sessions of CE prior to the acute assessment session. Seventy-two hours after the last session, the subjects were submitted to one session of CE (aerobic exercise: 25 min at 60–70% reserve heart rate and resistance exercise: 3 sets of 15 maximum repetitions of 6 exercises). Saliva samples were collected before, immediately, 6 and 24 hours after CE. Results: CE reduced cortisol (6 h: 2.54 [0.58] vs 0.65 [0.22] pg·mL−1; P = .02), increased testosterone (all moments) and immunoglobulin A levels (24 h: 255.3 [44.7] vs 349.2 [41.9] μm·mL−1; P = .01) without significant difference in cytokines levels in ILWHA. Conclusion: CE modulates cortisol, testosterone, and immunoglobulin A levels without the change in immunological parameters in ILWHA.
Cameron T. Gibbons, Polemnia G. Amazeen and Aaron D. Likens
Variability is commonly observed in complex behavior, such as the maintenance of upright posture. The current study examines the value added by using nonlinear measures of variability to identify dynamic stability instead of linear measures that reflect average fluctuations about a mean state. The largest Lyapunov exponent (λ1) and SD were calculated on mediolateral movement as participants performed a sit-to-stand task on a stable and unstable platform. Both measures identified changes in movement across postures, but results diverged when participants stood on the unstable platform. Large SD indicated an increase in movement variability, but small λ1 identified those movements as stable and controlled. The results suggest that a combination of linear and nonlinear analyses is useful in identifying the proportion of observed variability that may be attributed to structured, controlled sources. Nonlinear measures of variability, like λ1, can further be used to make predictions about transitions between stable postures and to identify a system’s resistance to disruption from external perturbations. Those features make nonlinear analyses highly applicable to both human movement research and clinical practice.
Estela Farías-Torbidoni and Demir Barić
Background: Protected areas are important attractions for promoting healthy life habits. Consequently, to date, a number of studies have examined the association between visitors’ characteristics and physical activities. However, little is known about the specific users inclined exclusively to have sedentary behavior during a visit. Thus, using the Alt Pirineu Natural Park (Spain) as a case study, the aim of this study is to determine the influence of sociodemographic, trip, motivational, and opinion descriptors on the likelihood of participating in sedentary behavior while visiting a protected natural area. Methods: The data used were randomly collected from visitors through an onsite structured questionnaire (N = 628). Results: Metabolic equivalent consumption was used to empirically distinguish the sedentary (22.6%) from the active (77.4%) visitor groups. A logistic regression analysis indicated that the trip and motivational descriptors explained the highest degree of the overall variation in reporting sedentary behavior. Conclusion: The study contributed to documenting the information about visitors’ behavior in protected areas, and the findings may aid park managers in developing effective management strategies for promoting and enhancing physical activity in protected natural areas.
Jordan Andre Martenstyn, Lauren Powell, Natasha Nassar, Mark Hamer and Emmanuel Stamatakis
Background: Previous epidemiological studies examining the association between physical activity (PA) and mortality risk have measured absolute PA intensity using standard resting metabolic rate reference values that fail to consider individual differences. This study compared the risk of all-cause and cardiovascular mortality between absolute and corrected estimates of PA volume. Methods: 49,982 adults aged ≥40 years who participated in the Health Survey for England and Scottish Health Survey in 1994–2008 were included in our study. PA was classified as absolute or corrected metabolic equivalent (MET)-hours per week, taking participant’s weight, height, age, and sex into account. Cox regression models were used to examine the association between absolute and corrected PA volumes and all-cause and cardiovascular mortality. Results: The authors found no difference in the association between levels of PA and risk of all-cause and cardiovascular mortality for absolute and corrected MET-hours per week, although there was a consistent decrease in mortality risk with increasing PA. There was no difference in mortality when analyses were stratified by sex, age, and body mass index. Conclusions: The association between PA volume and risk of mortality was similar regardless of whether PA volume was estimated using absolute or corrected METs. There is no empirical justification against the use of absolute METs to estimate PA volume from questionnaires.
Jeanette Gustat, Christopher E. Anderson, Keelia O’Malley, Tian Hu, Rachel G. Tabak, Karin Valentine Goins, Cheryl Valko, Jill S. Litt and Amy A. Eyler
Background: To assess how perceptions of the community built environment influence support for community policies that promote physical activity (PA). Methods: A national cross-sectional survey assessed perceptions of the local built environment and support of community policies, including school and workplace policies, promoting PA. A random digit–dialed telephone survey was conducted in US counties selected on Behavioral Risk Factor Surveillance System data for high or low prevalence of obesity and inactivity. A total of 1208 subjects were interviewed, 642 from high-prevalence counties and 566 from low-prevalence counties. Analyses were stratified by county prevalence of obesity and inactivity (high or low). Linear models adjusted for covariates were constructed to assess the influence of built environment perceptions on policy support. Results: Perception of more destinations near the residence was associated with increased support for community policies that promote PA, including tax increases in low-prevalence (obesity and inactivity) counties (P < .01). Positive perception of the workplace environment was associated (P < .001) with increased support for workplace policies among those in high-, but not low-, prevalence counties. Conclusions: Support for community policies promoting PA varies by perception of the built environment, which has implications for policy change.
Layne Case and Joonkoo Yun
Despite the rising interest in intervention for children with autism spectrum disorder, the extent to which interventions are effective on gross motor outcomes is currently unknown. The purpose of this study was to analyze the effect of different intervention approaches on gross motor outcomes among children with autism spectrum disorder using meta-analysis. A total of 18 studies met the inclusion criteria for quantitative analysis. Pre- and posttest means and SDs were extracted to calculate effect sizes. Potential moderator variables were chosen based on important intervention characteristics. The results suggest that interventions have a large effect on gross motor outcomes among children with autism spectrum disorder (δ = 0.99, SE = 0.19, p < .001, 95% confidence interval [0.62, 1.36]). The interventions that were 16 total hours or longer had a significantly larger effect than those less than 16 hr. In addition, the interventions in experimental settings had significantly larger effects than the interventions in practical settings. Future interventions should consider intensity, including not only the duration of the intervention but also the intensity in which specific intervention goals are targeted.
Iva Obrusnikova, Haley M. Novak and Albert R. Cavalier
Adults with intellectual disability have significantly lower musculoskeletal fitness than their peers without a disability. Appropriate instructional strategies are needed to facilitate their acquisition and maintenance of musculoskeletal fitness. In this multiple-baseline across-participants single-subject study, the authors evaluated the effects of a multicomponent package that included a video-enhanced system of least-to-most prompts on the acquisition of 5 muscle-strengthening exercises in 3 women with mild intellectual disability, age 24–37 yr. Results show substantive gains in correct and independent performance of steps in the 5 exercises during the treatment condition. The improved performance was maintained 2 wk after the last treatment session and in a large YMCA gym. The study suggests that use of the video-enhanced system of least-to-most prompts can lead to improved acquisition and maintenance of muscle-strengthening exercises by adults with mild intellectual disability.
Katrina M. Moss, Annette J. Dobson, Kimberley L. Edwards, Kylie D. Hesketh, Yung-Ting Chang and Gita D. Mishra
Background: Play equipment at home could be targeted in interventions to increase children’s physical activity (PA), but evidence is mixed, potentially because current methods do not reflect children’s lived experience. This study investigated associations between combinations of equipment and PA. Methods: Data were from the Mothers and their Children’s Health study and the Australian Longitudinal Study on Women’s Health. Mothers (n = 2409) indicated the types of fixed active (eg, trampolines), portable active (eg, bicycles), and electronic (eg, computers) equipment at home, and the number of days children (n = 4092, aged 5–12 y, 51% boys) met PA guidelines. Latent class analysis was used to identify combinations of equipment, and linear regressions were used to investigate associations with PA. Results: Compared with children with high active (fixed and portable) and medium electronic equipment, children with portable active and medium (B = −0.53; 95% confidence interval, −0.72 to −0.34) or high (B = −0.58; 95% confidence interval, −0.83 to −0.33) electronic equipment met the guidelines on fewer days. Children with similar active equipment (but more electronic equipment) met the PA guidelines on fewer days (mean difference = −0.51, SE = 0.14, P = .002). Conclusion: Having the right combination of play equipment at home may be important for children’s PA.
Kristy Martin, Kevin G. Thompson, Richard Keegan and Ben Rattray
The aim of this study was to investigate whether individuals who engage in more frequent self-regulation are less susceptible to mental fatigue. Occupational cognitive demand and participation in sports or exercise were quantified as activities requiring self-regulation. Cardiorespiratory fitness was also assessed. On separate occasions, participants either completed 90 min of an incongruent Stroop task (mental exertion condition) or watched a 90-min documentary (control condition). Participants then completed a cycling time-to-exhaustion (physical endurance) test. There was no difference in the mean time to exhaustion between conditions, although individual responses varied. Occupational cognitive demand, participation in sports or exercise, and cardiorespiratory fitness predicted the change in endurance performance (p = .026, adjusted R 2 = .279). Only cognitive demand added significantly to the prediction (p = .024). Participants who reported higher levels of occupational cognitive demand better maintained endurance performance following mental exertion.