Mark S. Tremblay
Mark S. Tremblay
Background: Emerging research shows that the composition of movement behaviors throughout the day (physical activities, sedentary behaviors, sleep) is related to indicators of health, suggesting previous research that isolated single movement behaviors maybe incomplete, misleading, and/or unnecessarily constrained. Methods: This brief report summarizes evidence to support a 24-hour movement behavior paradigm and efforts to date by a variety of jurisdictions to consult, develop, release, promote, and study 24-hour movement guidelines. It also introduces and summarizes the accompanying series of articles related specifically to 24-hour movement guidelines for the early years. Results: Using robust and transparent processes, Canada, Australia, New Zealand, South Africa, and the World Health Organization have developed and released 24-hour movement guidelines for the early years: an integration of physical activity, sedentary behavior, and sleep. Other countries are exploring a similar approach and related research is expanding rapidly. Articles related to guideline development in South Africa, the United Kingdom, Australia, and by the World Health Organization are a part of this special series. Conclusions: A new paradigm employing 24-hour movement guidelines for the early years that combines recommendations for movement behaviors across the whole day is gaining momentum across the globe.
Michelle R. Stone, Dale W. Esliger and Mark S. Tremblay
The purpose of this study was to determine the effects of age and leg length on the energy-expenditure predictions of five activity monitors. Participants (N = 86, ages 8–40 years) performed three progressive bouts of treadmill activity ranging from 4 to 12 km/hr. Differences between measured energy expenditure (VO2) and activity-monitor-predicted energy expenditure were assessed across five leg length categories to determine the influence of leg length. Accelerometer counts or pedometer steps along with age, weight, and leg length accounted for 85–94% of measured energy expenditure. The addition of age and leg length as predictor variables explained a larger amount of variance in energy expenditure across all speeds. Differences in leg length and age might affect activity-monitor validity and, therefore, should be controlled for when estimating physical activity energy expenditure.
Joey C. Eisenmann, P.T. Katzmarzyk and Mark S. Tremblay
In recent years, it has been noted that children and youth are physically inactive, and physical activity levels have declined over the past decades. However, few empirical studies have been conducted to test this assumption. Therefore, the purpose of this study was to examine leisure-time physical activity levels among Canadian adolescents 12–19 years of age.
Age, sex, geographic, and temporal trends in leisure-time physical activity energy expenditure (AEE) were examined using data from 5 national surveys conducted between 1981 and 1998. AEE was calculated from participants’ questionnaire responses on physical activity participation. General linear models were used to examine the differences in AEE across survey years, geographic regions, sexes, and age groups.
Males and 12–14-year-olds displayed greater AEE than females and 15–19-year-olds, respectively, and AEE was lowest in Quebec and highest in the West. AEE increased between the 1981 and 1988 surveys and has since remained relatively stable. The prevalence of subjects meeting the 12.6 kJ · kg−1 · d−1 (3 kcal · kg−1 · d−1) recommendation increased from 1981 to 1988. Since 1988, the prevalence of those meeting the 12.6 kJ · kg−1 · d−1 recommendation has decreased in 12–14 year old boys and remained relatively stable in the other groups. In 1998, about 45% of males and 35% of females met the 12.6 kJ · kg−1 · d−1 recommendation. In 1998, about 20% of 12–19-year-old males and 12–14-year-old females met the 25.1 kJ · kg−1 · d−1 (6 kcal · kg−1 · d−1) recommendation, while about 10% of 15–19-year-old females met this recommendation. In females, the prevalence of those meeting the 25.1 kJ · kg−1 · d−1 recommendation has remained relatively stable (about 10%) since 1981 except for an increase between 1996 and 1998 in 12–14-year-old girls. In males, a similar pattern, but not as dramatic, of that observed for the prevalence of those meeting the 12.6 kJ · kg−1 · d−1 emerged—that is, an increase between 1981 and 1988 and then a decrease in 12–14-year-old boys and a stable pattern in 15–19-year-old boys.
Although self-reported leisure-time physical activity appears to have increased since 1981, a majority of Canadian adolescents do not meet current recommendations for physical activity.
Meghann Lloyd, Rachel C. Colley and Mark S. Tremblay
John J. Reilly, Smita Dick, Geraldine McNeill and Mark S. Tremblay
The Active Healthy Kids Scotland Report Card aims to consolidate existing evidence, facilitate international comparisons, encourage more evidence-informed physical activity and health policy, and improve surveillance of physical activity.
Application of the Active Healthy Kids Canada Report Card process and methodology to Scotland, adapted to Scottish circumstances and availability of data.
The Active Healthy Kids Scotland Report Card 2013 consists of indicators of 7 Health Behaviors and Outcomes and 3 Influences on Health Behaviors and Outcomes. Grades of F were assigned to Overall Physical Activity, Sedentary Behavior (recreational screen time), and Obesity Prevalence. A C was assigned to Active Transportation and a D- was assigned to Diet. Two indicators, Active and Outdoor Play and Organized Sport Participation, could not be graded. Among the Influences, Family Influence received a D, while Perceived Safety, Access, and Availability of Spaces for Physical Activity and the National Policy Environment graded more favorably with a B.
The Active Healthy Kids Canada process and methodology was readily generalizable to Scotland. The report card illustrated low habitual physical activity and extremely high levels of screen-based sedentary behavior, and highlighted several opportunities for improved physical activity surveillance and promotion strategies.
Jennifer L. Copeland, Samuel Y. Chu and Mark S. Tremblay
Women experience significant changes in endocrine function during aging. Decreasing levels of anabolic hormones may be associated with musculoskeletal atrophy and decrease in function that is observed in older women and, as a result, there has been an increase in the use of pharmacological hormone therapies. It is difficult to distinguish, however, between physiological changes that are truly age related and those that are associated with lifestyle factors such as physical activity participation. Some research has shown that circulating levels of anabolic hormones such as DHEA(S) and IGF-I in older women are related to physical activity, muscle function, and aerobic power. Exercise-intervention studies have generally shown that increasing age blunts the acute hormonal response to exercise, although this might be explained by a lower exercise intensity in older women. There have been relatively few studies that examine hormonal adaptations to exercise training. Physical activity might have an effect on hormone action as a result of changes in protein carriers and receptors, and future research needs to clarify the effect of age and exercise on these other components of the endocrine system. The value and safety of hormone supplements must be examined, especially when used in combination with an exercise program.
Richard Larouche, Meghann Lloyd, Emily Knight and Mark S. Tremblay
The current investigation assessed the impact of active school transportation (AST) on average daily step counts, body mass index (BMI) and waist circumference in 315 children in Grades 4–6 who participated to Cycle 2 of the Canadian Assessment of Physical Literacy (CAPL) pilot testing. T-tests revealed a significant association between AST and lower BMI values (18.7 ± 3.3 vs. 19.9 ± 3.8 kg/m2). The active commuters accumulated an average of 662 more steps per day, and their waist circumference was lower by an average of 3.1 cm, but these differences were not statistically significant. ANCOVA analyses controlling for age and step counts, found trends toward lower BMI and waist circumference values among the active commuters. These results suggest that AST may be a valid strategy to prevent childhood obesity; further research is needed to determine more precisely the impact of AST on body composition, and the direction of the relationship.
Mark S. Tremblay, Joel D. Barnes and Jennifer Cowie Bonne
For 20 years Active Healthy Kids Canada (AHKC) has worked to inspire the country to engage all children and youth in physical activity (PA). The primary vehicle to achieve this is the AHKC Report Card on Physical Activity for Children and Youth, which has been released annually since 2005. Using 10 years of experience with this knowledge translation and synthesis mechanism, this paper aggregates and consolidates diverse evidence demonstrating the impact of the Report Card and related knowledge translation activities. Over the years many evaluations, consultations, assessments, and surveys have helped inform changes in the Report Card to improve its impact. Guided by a logic model, the various assessments have traversed areas related to distribution and reach, meeting stakeholder needs, use of the Report Card, its influence on policy, and advancing the mission of AHKC. In the past 10 years, the Report Card has achieved > 1 billion media impressions, distributed > 120,000 printed copies and > 200,000 electronic copies, and benefited from a collective ad value > $10 million. The Report Card has been replicated in 14 countries, 2 provinces, 1 state and 1 city. AHKC has received consistent positive feedback from stakeholders and endusers, who reported that the Report Card has been used for public awareness/education campaigns and advocacy strategies, to strengthen partnerships, to inform research and program design, and to advance and adjust policies and strategies. Collectively, the evidence suggests that the Report Card has been successful at powering the movement to get kids moving, and in achieving demonstrable success on immediate and intermediate outcomes, although the long-term goal of improving the PA of Canadian children and youth remains to be realized.
Meghann Lloyd, Travis J. Saunders, Emily Bremer and Mark S. Tremblay
The purpose of this study was to investigate the potential long-term association of motor skill proficiency at 6 years of age and self-reported physical activity (PA) at age 26. Direct motor performance data were collected in 1991 with a follow-up study occurring in 1996, and then indirect questionnaires (self-report) administered in 2001 and 2011. In 2011, 17 participants who were identified as either having high motor proficiency (HMP) or low motor proficiency (LMP) in 1991 completed a series of 4 questionnaires. Analyses were conducted to determine whether there were differences between groups for motor skill proficiency, PA, or sedentary behavior, and whether these outcomes were related across ages. Motor skill proficiency at age 6 was related to self-reported proficiency at age 16 (r = .77, p = .006), and self-reported proficiency between 16 and 26 years (r = .85, p = .001). Motor skill proficiency at age 6 was positively associated with leisure time PA at age 26 in females and participants in the HMP group. The results may provide preliminary evidence about the importance of how early motor skill proficiency relates to long-term PA. More research with larger sample sizes is needed to investigate the importance of motor skills over time.