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David M. Morris, Joshua R. Huot, Adam M. Jetton, Scott R. Collier and Alan C. Utter

Dehydration has been shown to hinder performance of sustained exercise in the heat. Consuming fluids before exercise can result in hyperhydration, delay the onset of dehydration during exercise and improve exercise performance. However, humans normally drink only in response to thirst, which does not result in hyperhydration. Thirst and voluntary fluid consumption have been shown to increase following oral ingestion or infusion of sodium into the bloodstream. We measured the effects of acute sodium ingestion on voluntary water consumption and retention during a 2-hr hydration period before exercise. Subjects then performed a 60-min submaximal dehydration ride (DR) followed immediately by a 200 kJ performance time trial (PTT) in a warm (30 °C) environment. Water consumption and retention during the hydration period was greater following sodium ingestion (1380 ± 580 mL consumed, 821 ± 367 ml retained) compared with placebo (815 ± 483 ml consumed, 244 ± 402 mL retained) and no treatment (782 ± 454 ml consumed, 148 ± 289 mL retained). Dehydration levels following the DR were significantly less after sodium ingestion (0.7 ± 0.6%) compared with placebo (1.3 ± 0.7%) and no treatment (1.6 ± 0.4%). Time to complete the PTT was significantly less following sodium consumption (773 ± 158 s) compared with placebo (851 ± 156 s) and no treatment (872 ± 190 s). These results suggest that voluntary hyperhydration can be induced by acute consumption of sodium and has a favorable effect on hydration status and performance during subsequent exercise in the heat.

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Phillip D. Tomporowski

Physical activity is purported to promote children’s brain health and enhance mental development (1). Three studies were selected for review because of their focus on issues that challenge translational research applications in exercise pediatric science. While some disagreement exists concerning the definition of translational research, most suggest that translational interventions focus on the uptake, implementation, and sustainability of research findings within standard care (2). Translational researchers typically highlight differences that exist between efficacy experiments, which provide evidence that a specific intervention works, and effectiveness experiments, which show that the intervention will reap benefits under real-world conditions. Results obtained from laboratory-based efficacy studies that have examined the relation between exercise and cognition led researchers (3,4) and policy makers to consider the importance of physical activity in school settings. Large-scale studies that assess the impact of various types of school based physical activity intervention on children’s cognitive and academic performance have begun. The initial results have been uneven and suggestive of a lack of benefit for children in authentic school settings. Before drawing such conclusions, however, it will be important for researchers and practitioners to recognize the methodological and measurement issues that challenge attempts to employ laboratory methodologies to academic settings.

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Lena Fleig, Megan M. McAllister, Penny Brasher, Wendy L. Cook, Pierre Guy, Joseph H. Puyat, Karim M. Khan, Heather A. McKay and Maureen C. Ashe

Objectives:

To characterize patterns of sedentary behavior and physical activity in older adults recovering from hip fracture and to determine characteristics associated with activity.

Methods:

Community-dwelling, Canadian adults (65 years+) who sustained hip fracture wore an accelerometer at the waist for seven days and provided information on quality of life, falls self-efficacy, cognitive functioning, and mobility.

Results:

There were 53 older adults (mean age [SD] 79.5 [7.8] years) enrolled in the study; 49 had valid data and demonstrated high levels of sedentary time (median [p10, p90] 591.3 [482.2, 707.2] minutes/day), low levels of light activity (186.6 [72.6, 293.7]), and MVPA (2 [0.1, 27.6]), as well as few daily steps (2467.7 [617.1, 6820.4]). Regression analyses showed that age, gender, gait speed, and time since fracture were associated with outcomes.

Conclusions:

Older adults have long periods of sedentary time with minimal activity. Results are a call to action to encourage people to sit less and move more.

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Meghan Baruth and Sara Wilcox

Background:

Understanding who is most and least likely to remain active after the completion of physical activity (PA) interventions can assist in developing more targeted and effective programs to enhance prolonged behavior change. The purpose of this study was to examine predictors of meeting PA recommendations 6 months postintervention in participants enrolled in Active for Life.

Methods:

Participants from 2 behavioral PA programs [158 Active Choices (AC); 1025 Active Living Every Day (ALED)] completed surveys 6 months after completion of the active intervention. Analyses examined predictors of meeting PA recommendations at follow-up.

Results:

The following were significant predictors: In ALED: self-report health status, satisfaction with body function, and self-efficacy at baseline; PA status at posttest; changes in self-efficacy, perceived stress, and satisfaction with body function and appearance from baseline to posttest. In AC: PA status at posttest.

Conclusions:

The ultimate goal of health promotion programs is to teach the behavioral skills necessary to sustain behavior change once an active intervention is complete. The findings from this study suggest that predicting PA behavior after cessation of PA interventions may not be straightforward, and predictor variables may operate differently in different intervention approaches.

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Mitch J. Duncan, Hannah M. Badland and William Kerry Mummery

Background:

The aim of this study was to examine the relationship between occupational category and 3 health-related behaviors: participation in leisure-time physical activity, active transport (AT) and occupational sitting in a sample of employed Australian adults.

Methods:

A random, cross-sectional sample of 592 adults aged 18 to 71 years completed a telephone survey in October/November 2006. Reported occupations were categorized as professional (n = 332, 56.1%), white-collar (n = 181, 30.6%), and blue-collar (n = 79, 13.3%). Relationships between occupational category and AT, sufficient physical activity and occupational sitting were examined using logistic regression.

Results:

White-collar employees (OR = 0.36, 95% CI 0.14−0.95) were less likely to engage in AT and more likely to engage in occupational sitting (OR = 3.10, 95% CI 1.63−5.92) when compared with blue-collar workers. Professionals (OR = 3.04, 95% CI 1.94−4.76) were also more likely to engage in occupational sitting compared with blue-collar workers. No relationship was observed between occupational category and engagement in sufficient physical activity.

Conclusions:

No association between occupational category and sufficient physical activity levels was observed, although white-collar and professionals were likely to engage in high levels of occupational sitting. Innovative and sustainable strategies are required to reduce occupational sitting to improve health.

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Glen Nielsen, Rachael Taylor, Sheila Williams and Jim Mann

Background:

To investigate whether the number of permanent playground facilities in schools influences objectively measured physical activity.

Methods:

Physical activity was measured using Actical accelerometers over 2 to 5 days in 417 children (5–12 years) from 7 schools. The number of permanent play facilities likely to encourage physical activity in individuals or groups of children (eg, adventure playgrounds, swings, trees, playground markings, courts, sandpits) were counted on 2 occasions in each school. The surface area of each playground (m2) was also measured.

Results:

The number of permanent play facilities in schools ranged from 14 to 35 and was positively associated with all measures of activity. For each additional play facility, average accelerometry counts were 3.8% (P < .001) higher at school and 2.7% (P < .001) higher overall. Each additional play facility was also associated with 2.3% (P = .001) or 4 minutes more moderate/vigorous activity during school hours and 3.4% (P < .001) more (9 minutes) over the course of the day. School playground area did not affect activity independent of the number of permanent play facilities. Findings were consistent across age and sex groups.

Conclusion:

Increasing the number of permanent play facilities at schools may offer a cost-effective and sustainable option for increasing physical activity in young children.

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Jason Duvall

Background:

This study investigated the effectiveness of enhanced cognitive awareness as a means of encouraging outdoor walking. An intervention using engagement-based strategies was compared with a more traditional walking intervention focused on developing and committing to a personalized walking schedule.

Methods:

117 adults were randomly assigned to 1 of 2 treatments—Standard Care (schedule setting, commitment) or Engagement (awareness plans)—and asked to take at least 3, 30 minute outdoor walks each week for 2 weeks. During the study period, self-report and objective measures were used to collect data on walking behavior.

Results:

Individuals in both treatment conditions reported significant increases (P < .05) in walking behavior. Participants in both treatments failed to sustain these increases at a follow-up measure 4 weeks later. However, the Engagement condition was particularly effective for those individuals who had less prior experience maintaining a walking routine.

Conclusion:

Overall, the findings suggest it may be beneficial to incorporate engagement-based strategies into existing walking interventions. Results of this study also raise the possibility that efforts to encourage cognitive awareness may make the outdoor walking experience more interesting and enjoyable.

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Dana Sirota, Dodi Meyer, Andres Nieto, Arlen Zamula, Melissa Stockwell and Evelyn Berger-Jenkins

Background:

School-based physical activity programs can reach large populations of at-risk children however evidence for the sustainability of healthy behaviors as a result of these programs is mixed. Healthy Schools Healthy Families (HSHF) is a physical activity and nutrition program for elementary students in a predominantly minority community. The program includes short teacher led classroom-based physical activities, also known as Transition Exercises (TE). Our aim was to assess whether TE was associated with children’s reported recreational physical activity outside of school.

Methods:

We surveyed HSHF students in grade 5 (n = 383) about their recreational physical activity at the start and end of the school year. Multivariable analysis was used to determine what factors including TE contributed to their reported activity.

Results:

Students were predominantly Hispanic with a mean age of 10 ± .03. There was an increase in reported recreational physical activity from the start to the end of the school year (73.6% to 82.4%, P < .05). Students who participated in more TE had a 2.75 times greater odds of reporting participation in recreational activity than students who participated in less TE.

Conclusions:

For students in HSHF, TE was significantly associated with an increase in recreational physical activity.

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Maciej S. Buchowski, Leena Choi, Karen M. Majchrzak, Sari Acra, Charles E. Matthews and Kong Y. Chen

Background:

Environmental factors including seasonal changes are important to guide physical activity (PA) programs to achieve or sustain weight loss. The goal was to determine seasonal variability in the amount and patterns of free-living PA in women.

Methods:

PA was measured in 57 healthy women from metropolitan Nashville, TN, and surrounding counties (age: 20 to 54 years, body mass index: 17 to 48 kg/m2) using an accelerometer for 7 consecutive days during 3 seasons within 1 year. PA counts and energy expenditure (EE) were measured in a whole-room indirect calorimeter and used to model accelerometer output and to calculate daily EE and intensity of PA expressed as metabolic equivalents (METs).

Results:

PA was lower in winter than in summer (131 ± 45 vs. 144 ± 54 × 103 counts/d; P = .025) and in spring/fall (143 ± 48 × 103 counts/d; P = .027). On weekends, PA was lower in winter than in summer by 22,652 counts/d (P = .008). In winter, women spent more time in sedentary activities than in summer (difference 35 min/d; P = .007) and less time in light activities (difference −29 min/d, P = .018) and moderate or vigorous activities (difference −6 min/d, P = .051).

Conclusions:

Women living in the southeastern United States had lower PA levels in winter compared with summer and spring/fall, and the magnitude of this effect was greater on weekends than weekdays.

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Naroa Etxebarria, Shaun D’Auria, Judith M. Anson, David B. Pyne and Richard A. Ferguson

Purpose:

The patterns of power output in the ~1-h cycle section of Olympic-distance triathlon races are not well documented. Here the authors establish a typical cycling-race profile derived from several International Triathlon Union elite-level draftinglegal triathlon races.

Methods:

The authors collated 12 different race power profiles from elite male triathletes (N = 5, age 25 ± 5 y, body mass 65.5 ± 5.6 kg; mean ± SD) during 7 international races. Power output was recorded using SRM cranks and analyzed with proprietary software.

Results:

The mean power output was 252 ± 33 W, or 3.9 ± 0.5 W/kg in relative terms, with a coefficient of variation of 71% ± 13%. Normalized power (power output an athlete could sustain if intensity were maintained constant without any variability) for the entire cycle section was 291 ± 29 W, or 40 ± 13 W higher than the actual mean power output. There were 34 ± 14 peaks of power output above 600 W and ~18% time spent at >100% of maximal aerobic power.

Conclusion:

Cycling during Olympic-distance triathlon, characterized by frequent and large power variations including repeat supramaximal efforts, equates to a higher workload than cycling at constant power.