Ronald C. Plotnikoff

Randomized Controlled Trial of the Effects of Print Materials and Step Pedometers on Physical Activity and Quality of Life in Breast Cancer Survivors

PURPOSE To determine the effects of breast cancer-specific print materials and step pedometers on physical activity (PA) and quality of life (QoL) in breast cancer survivors. PATIENTS AND METHODS Breast cancer survivors (N = 377) were randomly assigned to receive one of the following: a standard public health recommendation for PA, previously developed breast cancer-specific PA print materials, a step pedometer, or a combination of breast cancer-specific print materials and step pedometers. The primary outcome was self-reported moderate/vigorous PA minutes per week. Secondary outcomes were QoL (Functional Assessment of Cancer Therapy-Breast), fatigue, self-reported brisk walking, and objective step counts. Assessments were conducted at baseline and postintervention (12 weeks). RESULTS Attrition was 10.3% (39 of 377). On the basis of linear mixed-model analyses, PA increased by 30 minutes/week in the standard recommendation group compared with 70 minutes/week in the print material group (mean difference, 39 minutes/week; 95% CI = -10 to 89; d = 0.25; P = .117), 89 minutes/week in the pedometer group (mean difference, 59 minutes/week; 95% CI, 11 to 108; d = 0.38; P = .017), and 87 minutes/week in the combined group (mean difference, 57 minutes/week; 95% CI, 8 to 106; d = 0.37; P = .022). For brisk walking minutes/week, all three intervention groups reported significantly greater increases than the standard recommendation group. The combined group also reported significantly improved QoL (mean difference, 5.8; 95% CI, 2.0 to 9.6; d = 0.33; P = .003) and reduced fatigue (mean difference, 2.3; 95% CI, 0.0 to 4.7; d = 0.25; P = .052) compared with the standard recommendation group. CONCLUSION Breast cancer-specific PA print materials and pedometers may be effective strategies for increasing PA and QoL in breast cancer survivors. A combined approach appears to be optimal. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov Identifier NCT00221221

Resistance Training and Type 2 Diabetes: Considerations for implementation at the population level

Aerobic exercise has consistently been shown to improve glucose control (1–3), enhance insulin sensitivity (2,4,5), and improve cardiovascular risk factors such as visceral adiposity (2), lipid profile (6), arterial stiffness (7), and endothelial function (8). Consistent with this evidence, the American Diabetes Association (ADA) recommends that individuals with type 2 diabetes perform at least 150 min of moderate-intensity aerobic exercise and/or at least 90 min of vigorous aerobic exercise per week (9). Although a lifestyle modification of this nature could have substantial impact on the metabolic and cardiovascular health of this population, it is often difficult for those who have been habitually sedentary to adhere to these guidelines. Indeed, a recent population-based study found that only 28% of individuals with type 2 diabetes achieve these recommendations (10). Unfortunately, it is frequently those who would benefit the most from aerobic exercise that have the greatest difficulty performing it. For individuals with severe obesity, arthritis, physical disabilities, and/or diabetes complications, even walking for 20–30 min may be challenging, uncomfortable, and/or painful to perform. With the continued increase in the prevalence of type 2 diabetes (11), it is evident that alternate forms of physical activity that produce similar metabolic improvements to aerobic exercise may be beneficial in the management of this disease. Resistance training has recently been recognized as a useful therapeutic tool for the treatment of a number of chronic diseases (12–19) and has been demonstrated to be safe and efficacious for the elderly (20,21) and obese (22) individuals. Similar to aerobic exercise, resistance training has been reported to enhance insulin sensitivity (23–25), daily energy expenditure (26,27), and quality of life (20,28). Furthermore, resistance training has the potential for increasing muscle strength (13,29, …

Efficacy of a workplace-based weight loss program for overweight male shift workers: the Workplace POWER (Preventing Obesity Without Eating like a Rabbit) randomized controlled trial

OBJECTIVE To evaluate the feasibility and efficacy of a workplace-based weight loss program (Workplace POWER-WP) for male shift workers. METHOD A prospective, two-armed randomized controlled trial of 110 overweight/obese (BMI 25-40) (mean [SD] age = 44.4 [8.6] years; BMI = 30.5 [3.6]) male employees at Tomago Aluminium aged 18-65. In October (2009) men were randomized to either (i) WP program (n=65) or (ii) a 14-week wait-list control group (n=45). The 3-month program involved one information session, program booklets, group-based financial incentives and an online component. Men were assessed at baseline and at 14-week follow-up for weight (primary outcome), waist circumference, BMI, blood pressure, resting heart rate, self-reported physical activity and dietary variables, and physical activity and dietary cognitions. RESULTS Intention-to-treat analysis using linear mixed models revealed significant between group differences for weight loss after 14 weeks (P < .001, Cohens d = 0.34). Significant intervention effects were also found for waist circumference (P < .001, d = 0.63), BMI (P < .001, d = 0.41), systolic blood pressure (P = .02, d = 0.48), resting heart rate (P < .001, d = 0.81), physical activity (P = .03, d = 0.77), sweetened beverages (P < .02, d = 0.5-0.6) and physical activity-related cognitions (P < .02, d=0.6). CONCLUSION The WP program was feasible and efficacious and resulted in significant weight loss and improved health-related outcomes and behaviours in overweight male shift workers.

Efficacy of an E-mail intervention for the promotion of physical activity and nutrition behavior in the workplace context.

Purpose. The purpose of this study was to evaluate a 12-week workplace e-mail intervention designed to promote physical activity and nutrition behavior. Design. A pre- and post-test design was conducted to compare the effects of e-mail messages between intervention and control groups. Setting. Five large workplaces in Alberta, Canada. Subjects. Employees with access to a personal e-mail address (N = 2121) were randomly assigned to an intervention (n = 1566) or a control group (n = 555). Intervention. Physical activity and nutrition messages were based on social-cognitive theories. The intervention group received one physical activity and one parallel nutrition message per week for 12 weeks. The control group received no weekly messages. Measures. Each participant completed self-report measures of physical activity and nutrition related to knowledge, attitudes, and behaviors 1 week before (time 1) and 1 week after (time 2) the intervention. Results. The intervention group was more efficacious at time 2 on measures of self-efficacy, pros, cons, intentions, and behavior related to physical activity. This group also reported more favorable changes in practicing healthy eating, balancing food intake with activity level, cooking meals with techniques to reduce fat, and avoiding eating high-fat foods. Effect sizes for all significant differences were small. Conclusion. E-mail is a promising mode of delivery for promoting physical activity and nutrition in the workplace. Further theoretically driven studies are needed.

Predicting exercise stage transitions over two consecutive 6-month periods : A test of the theory of planned behaviour in a population-based sample

OBJECTIVES To predict exercise stage transitions over two consecutive 6-month periods using the theory of planned behaviour (TPB). It was hypothesized that different social cognitive constructs would predict different stage transitions. DESIGN Prospective and longitudinal in order to predict multiple stage transitions over time. Assessments were made at baseline, 6 months and 1 year. METHOD Participants were a randomly selected population-based sample of 683 adults who completed two telephone interviews (baseline and 6 months) that assessed exercise stage, intention, perceived behavioural control, attitude, subjective norm, and social support, and a mailed survey (1 year) that assessed exercise stage. RESULTS Progression from pre-contemplation was predicted by intention, attitude and subjective norm; progression/regression from contemplation was predicted by intention, perceived behavioural control, attitude, and social support; progression/regression from preparation was predicted by intention and attitude; and regression from action/maintenance was predicted by intention, attitude and social support. CONCLUSIONS Different social cognitive constructs predicted different stage transitions, which indicates that exercise behaviour change may be represented by a series of stage transitions. Moreover, the TPB may be a useful model for highlighting the key social cognitive constructs that are important for exercise stage transitions.

Prediction of leisure-time walking: an integration of social cognitive, perceived environmental, and personality factors

BackgroundWalking is the primary focus of population-based physical activity initiatives but a theoretical understanding of this behaviour is still elusive. The purpose of this study was to integrate personality, the perceived environment, and planning into a theory of planned behaviour (TPB) framework to predict leisure-time walking.MethodsParticipants were a random sample (N = 358) of Canadian adults who completed measures of the TPB, planning, perceived neighbourhood environment, and personality at Time 1 and self-reported walking behaviour two months later.ResultsAnalyses using structural equation modelling provided evidence that leisure-time walking is largely predicted by intention (standardized effect = .42) with an additional independent contribution from proximity to neighbourhood retail shops (standardized effect = .18). Intention, in turn, was predicted by attitudes toward walking and perceived behavioural control. Effects of perceived neighbourhood aesthetics and walking infrastructure on walking were mediated through attitudes and intention. Moderated regression analysis showed that the intention-walking relationship was moderated by conscientiousness and proximity to neighbourhood recreation facilities but not planning.ConclusionOverall, walking behaviour is theoretically complex but may best be addressed at a population level by facilitating strong intentions in a receptive environment even though individual differences may persist.

Validation of the Decisional Balance Scales in the Exercise Domain From the Transtheoretical Model: A Longitudinal Test

This study examined the validity and reliability of decisional balance scales for exercise (i.e., pros and cons) in a large longitudinal population-based randomized sample of Canadian adults ages 18 to 65 years (N = 703). Assessments were taken over 3 time points with 6-month intervals between testing. Content, factorial, concurrent, and construct validity along with internal consistency and test-retest reliability were established for the decisional balance scales. The developed measures have utility for researchers and practitioners who test and apply the exercise decisional balance constructs of the Transtheoretical Model.

Physical Activity and Diabetes

• Moderate to high levels of physical activity and cardiorespiratory fitness are associated with substantially lower morbidity and mortality in people with diabetes. • Both aerobic and resistance exercise are beneficial, and it is optimal to do both types of exercise. At least 150 minutes per week of aerobic exercise and at least 2 sessions per week of resistance exercise are recommended, though smaller amounts of activity still provide some health benefits. • A number of strategies that increase self-efficacy and motivation can be employed to increase physical activity uptake and maintenance, such as setting specific physical activity goals, using self-monitoring tools (pedometers or accelerometers) and developing strategies to overcome anticipated barriers. • For people with type 2 diabetes, supervised exercise programs have been particularly effective in improving glycemic control, reducing the need for noninsulin antihyperglycemic agents and insulin, and producing modest but sustained weight loss. • Habitual, prolonged sitting is associated with increased risk of death and major cardiovascular events.

Exercise Behavior in a Community Sample With Diabetes: Understanding the Determinants of Exercise Behavioral Change

PURPOSE The purpose of this study was to investigate the factors associated with exercise behavior among adults with diabetes. METHODS Exercise behavior (stage of exercise readiness and energy expenditure) and potential determinants were measured on a subsample (n=46) of adults with type 1 or type 2 diabetes from a randomized population-based telephone survey. Participants were assessed at baseline and at a 6-month follow-up. RESULTS Sociodemographic and biomedical characteristics did not significantly differ between the stages of exercise behavior. Scores on the psychosocial constructs of self-efficacy, behavioral processes, self-concept, and social support were significantly higher for those in the action stage than those in the preaction stage of exercise readiness. Self-efficacy and behavioral process of change were significantly associated with energy expenditure; self-efficacy was the strongest predictor in the longitudinal analysis. CONCLUSIONS These findings may generate direction for theory development and guide health and medical practitioners when intervening on the specific constructs. Populationand community-based surveys have utility for assessing diabetes health-related behavior (eg, exercise behavior).

Preventing Obesity Among Adolescent Girls: One-Year Outcomes of the Nutrition and Enjoyable Activity for Teen Girls (NEAT Girls) Cluster Randomized Controlled Trial

OBJECTIVE To evaluate the impact of a 12-month multicomponent school-based obesity prevention program, Nutrition and Enjoyable Activity for Teen Girls among adolescent girls. DESIGN Group randomized controlled trial with 12-month follow-up. SETTING Twelve secondary schools in low-income communities in the Hunter and Central Coast regions of New South Wales, Australia. PARTICIPANTS Three hundred fifty-seven adolescent girls aged 12 to 14 years. INTERVENTION A multicomponent school-based intervention program tailored for adolescent girls. The intervention was based on social cognitive theory and included teacher professional development, enhanced school sport sessions, interactive seminars, nutrition workshops, lunch-time physical activity sessions, handbooks and pedometers for self-monitoring, parent newsletters, and text messaging for social support. MAIN OUTCOME MEASURES Body mass index (BMI, calculated as weight in kilograms divided by height in meters squared), BMI z score, body fat percentage, physical activity, screen time, dietary intake, and self-esteem. RESULTS After 12 months, changes in BMI (adjusted mean difference, -0.19; 95% CI, -0.70 to 0.33), BMI z score (mean, -0.08; 95% CI, -0.20 to 0.04), and body fat percentage (mean, -1.09; 95% CI, -2.88 to 0.70) were in favor of the intervention, but they were not statistically different from those in the control group. Changes in screen time were statistically significant (mean, -30.67 min/d; 95% CI, -62.43 to -1.06), but there were no group by time effects for physical activity, dietary behavior, or self-esteem. CONCLUSIONS A school-based intervention tailored for adolescent girls from schools located in low-income communities did not significantly reduce BMI gain. However, changes in body composition were of a magnitude similar to previous studies and may be associated with clinically important health outcomes. TRIAL REGISTRATION anzctr.org.au Identifier: 12610000330044.