Physical Activity In Sedentary Adults Research Articles

Idiographic Dynamic Modeling for Behavioral Interventions with Mixed Data Partitioning and Discrete Simultaneous Perturbation Stochastic Approximation.

This paper presents the use of discrete simultaneous perturbation stochastic approximation (DSPSA) as a routine method to efficiently determine features and parameters of idiographic (i.e. single subject) dynamic models for personalized behavioral interventions using various partitions of estimation and validation data. DSPSA is demonstrated as a valuable method to search over model features and regressor orders of AutoRegressive with eXogenous input estimated models using participant data from Just Walk (a behavioral intervention to promote physical activity in sedentary adults); results of DSPSA are compared to those of exhaustive search. In Just Walk, DSPSA efficiently and quickly estimates models of walking behavior, which can then be used to develop control systems to optimize the impacts of behavioral interventions. The use of DSPSA to evaluate models using various partitions of individual data into estimation and validation data sets also highlights data partitioning as an important feature of idiographic modeling that should be carefully considered.

A Kalman filter-based Hybrid Model Predictive Control Algorithm for Mixed Logical Dynamical Systems: Application to Optimized Interventions for Physical Activity.

Hybrid Model Predictive Control (HMPC) is presented as a decision-making tool for novel behavioral interventions to increase physical activity in sedentary adults, such as Just Walk. A broad-based HMPC formulation for mixed logical dynamical (MLD) systems relevant to problems in behavioral medicine is developed and illustrated on a representative participant model arising from the Just Walk study. The MLD model is developed based on the requirement of granting points for meeting daily step goals and categorical input variables. The algorithm features three degrees-of-freedom tuning for setpoint tracking, measured and unmeasured disturbance rejection that facilitates controller robustness; disturbance anticipation further improves performance for upcoming events such as weekends and weather forecasts. To avoid the corresponding mixed-integer quadratic problem (MIQP) from becoming infeasible, slack variables are introduced in the objective function. Simulation results indicate that the proposed HMPC scheme effectively manages hybrid dynamics, setpoint tracking, disturbance rejection, and the transition between the two phases of the intervention (initiation and maintenance) and is suitable for evaluation in clinical trials.

A Group-based Digital Exercise Intervention Improves Physical Activity In Sedentary Adults

A Group-based Digital Exercise Intervention Improves Physical Activity In Sedentary Adults

Exercise Intervention Outcomes with Cannabis Users and Nonusers Aged 60 and Older.

Objectives: Cannabis use is increasing among older adults. We examined whether cannabis use impacted results of an intervention to increase physical activity in sedentary adults aged 60 and over. Methods: We measured differences in body mass index (BMI), exercise behavior, and cardiovascular fitness between older adult cannabis users (N = 28) and nonusers (N = 136) participating in an exercise intervention trial. Results: BMI of cannabis users was significantly lower than non-users (p = .007). Cannabis users reported .70 more days of exercise on the Stanford 7-Day Physical Activity Recall than non-users at the 8-week timepoint (p = .068) and were 4.1 points higher on the exercise subscale of the Community Healthy Activities Model Program for Seniors at 16-weeks (p = .045). Neither baseline nor post-intervention fitness differed by cannabis use status, and cardiovascular fitness improved after intervention in the full sample. Conclusion: These preliminary data suggest that current cannabis use status is not associated with a negative impact on fitness and efforts to increase exercise in sedentary older adults. Future studies should collect more detailed information on patterns and forms of cannabis use to understand their potential health effects for older adults.

Token‐economy‐based contingency management increases daily steps in adults with developmental disabilities

AbstractAdults with developmental disabilities are less likely to meet physical activity guidelines than typically developing counterparts. Contingency management (CM) interventions increase physical activity in sedentary adults. The current study systematically replicated previous research among sedentary adults diagnosed with developmental disabilities living in a residential group home, using a token economy in the context of a CM intervention. Using a changing criterion design, participants (N = 4) were given tokens contingent on meeting increasing step goals over 8 weeks, tracked via a Fitbit Flex™. CM increased the number of steps substantially for three of four participants. These findings extend previous research supporting the use of token‐based CM interventions for increasing daily steps among individuals with developmental disabilities. Because the current study was conducted in a residential group home setting, it may offer a long‐term sustainable approach to improving the health of some individuals living with developmental disabilities.

Adults Want to Play Too: Feasibility of an Adult Physical Activity Program Designed to Maximize Enjoyment

Few adults in the United States obtain sufficient physical activity (PA) despite knowledge of the associated health benefits. The current feasibility study examined the feasibility of a novel modified sports intervention designed to promote enjoyment and sustained PA in sedentary adults. The US adults (N = 22, mean age 39.2y, male/female percentage 54.5/45.5) in Central Pennsylvania participated in the PlayFit sports program for 60-minute sessions, 2 to 3times per week, over the course of 10 weeks and 24 game sessions; completing 198 person sessions collectively. Primary outcomes were PA (accelerometry) and intervention satisfaction. Percentage of time in moderate to vigorous activity ranged from 35.0% (volleyball) to 91.2% (ultimate frisbee). Percentage of time spent in vigorous activity ranged from 0.0% (volleyball) to 29.5% (team handball). Satisfaction, based on a 10-point scale with 10 being the most satisfied, ranged from 7.7 (kickball) to 8.7 (floor hockey and soccer). On average, all sports were rated highly, with the majority rated >8.5 and one rated <8.0. Percentage of time spent in the moderate to vigorous range was lower in men than in women (73.2% vs 80.0%, P = .01), but did not differ by age or body mass index. PlayFit is a promising first step in exploring the potential of modified sports programs to enhance population PA levels.

Practical Considerations for Data Collection and Management in Mobile Health Micro-randomized Trials.

There is a growing interest in leveraging the prevalence of mobile technology to improve health by delivering momentary, contextualized interventions to individuals' smartphones. A just-in-time adaptive intervention (JITAI) adjusts to an individual's changing state and/or context to provide the right treatment, at the right time, in the right place. Micro-randomized trials (MRTs) allow for the collection of data which aid in the construction of an optimized JITAI by sequentially randomizing participants to different treatment options at each of many decision points throughout the study. Often, this data is collected passively using a mobile phone. To assess the causal effect of treatment on a near-term outcome, care must be taken when designing the data collection system to ensure it is of appropriately high quality. Here, we make several recommendations for collecting and managing data from an MRT. We provide advice on selecting which features to collect and when, choosing between "agents" to implement randomization, identifying sources of missing data, and overcoming other novel challenges. The recommendations are informed by our experience with HeartSteps, an MRT designed to test the effects of an intervention aimed at increasing physical activity in sedentary adults. We also provide a checklist which can be used in designing a data collection system so that scientists can focus more on their questions of interest, and less on cleaning data.

System Identification of Just Walk: Using Matchable-Observable Linear Parametrizations

System identification approaches have been used to design an experiment, generate data, and estimate dynamical system models for Just Walk, a behavioral intervention intended to increase physical activity in sedentary adults. The estimated models serve a number of important purposes, such as understanding the factors that influence behavior and as the basis for using control systems as decision algorithms in optimized interventions. A class of identification algorithms known as matchable-observable linear identification has been reformulated and adapted to estimate linear time-invariant models from data obtained from this intervention. The experimental design, estimation algorithms, and validation procedures are described, with the best models estimated from data corresponding to an individual intervention participant. The results provide insights into the individual and the intervention, which can be used to improve the design of future studies.

Acute and chronic caffeine administration increases physical activity in sedentary adults

Caffeine is a commonly used stimulant thought to have ergogenic properties. Most studies on the ergogenic effects of caffeine have been conducted in athletes. The purpose of this study was to test the hypothesis that caffeine reduces ratings of perceived exertion and increases liking of physical activity in sedentary adults. Participants completed treadmill walking at 60% to 70% of their maximal heart rate at baseline and for 6 subsequent visits, during which half of the participants were given caffeine (3 mg/kg) and half given placebo in a sports drink vehicle. To investigate the potential synergistic effects of acute and chronic caffeine on self-determined exercise duration, participants were rerandomized to either the same or different condition for the last visit, creating 4 chronic/acute treatment groups (placebo/placebo, placebo/caffeine, caffeine/placebo, caffeine/caffeine). Participants rated how much they liked the activity and perceived exertion at each visit. There was a main effect of time on liking of physical activity, with liking increasing over time and an interaction of sex and caffeine treatment on liking, with liking of activity increasing in female participants treated with caffeine, but not with placebo. There was no effect of caffeine on ratings of perceived exertion. Individuals who received caffeine on the final test day exercised for significantly longer than those who received placebo. These data suggest that repeated exposure to physical activity significantly increases liking of exercise and reduces ratings of perceived exertion and that caffeine does little to further modify these effects.

Using Pedometers to Promote Physical Activity Among Clinical Populations

Using Pedometers to Promote Physical Activity Among Clinical Populations

Modelling multiple outcomes to improve the detection of causal mediation effects in complex intervention trials

Aim In a trial to increase physical activity in sedentary adults, there was no evidence of effect on the primary outcome, though large significant effects amongst eight related SF36 measures of general health [1]. How could such differences arise? Could they be: a true effect mediated through receiving the intervention, another systematic effect such as self-reporting bias, and/or chance? The aim was to develop reliable methods to investigate whether effects of the intervention on the SF36 outcomes were mediated through truly receiving the intervention delivered in intervention sessions.

Cost-effectiveness of alternative approaches for motivating activity in sedentary adults: Results of Project STRIDE

Objective. To evaluate the cost-effectiveness of non-face-to-face interventions for increasing physical activity in sedentary adults. The study took place in Providence, Rhode Island between the years 2000 and 2004. Methods. Two hundred and thirty-nine participants were randomized to Phone, Print or a contact control. Phone and Print groups were mailed regular surveys regarding their level of physical activity, motivational readiness and self-efficacy. Surveys were scanned by a computer expert system to generate feedback reports. Phone group participants received feedback by telephone. Print group participants received feedback by mail. The contact control group received mailings unrelated to physical activity. Intervention costs were assessed prospectively, from a payer perspective. Physical activity was measured using the 7-day Physical Activity Recall. Ambulatory health service use was assessed via monthly surveys. Results. The Print intervention was more economically efficient than the Phone intervention in engaging participants in a more active lifestyle. Conclusion. The Print intervention provides an efficient approach to increasing physical activity. Research is needed to determine the cost-effectiveness of the intervention in a more diverse population, within the context of the health service delivery system and over a longer period of time.

The Association between Mood States and Physical Activity in Postmenopausal, Obese, Sedentary Women

Mood states influence evaluative judgments that can affect the decision to exercise or to continue to exercise. This study examined how mood associated with graded exercise testing (GXT) in sedentary, obese, postmenopausal women (N = 25) was associated with physical activity and predicted VO2max during and after a behavioral weight-loss program (BWLP). Measures of physical activity included planned exercise, calories from physical activity, leisure-time physical activity, and predicted VO2max. Mood before and after pre-BWLP GXT was assessed using the Profile of Mood States. Mood before and after the GXT was more strongly associated with planned exercise than other forms of physical activity, and this effect became stronger over time. Mood enhancement in response to exercise was not related to physical activity. Mood before and after exercise might yield important clinical information that can be used to promote physical activity in sedentary adults.

PROJECT PRIME

Project PRIME is a randomized clinical trial to compare Lifestyle Group (PRIME G, n = 112), Lifestyle Correspondent (PRIME C, n = 128), and YMCA Standard Care control (PRIME SC, n = 138) interventions to increase physical activity in sedentary adults. Participants were overweight but healthy men (51%) and women (49%) aged 35–75 years at baseline, including 62% Caucasian, 19% Hispanic, and 17% African Americans. Participants were randomized in 4 cohorts blocked by gender. PRIME G received a Lifestyle curriculum in a group setting, while PRIME C received the same curriculum by telephone and mail. PRIME SC received a free YMCA membership. Participants completed a ramped bicycle ergometer test to measure endurance fitness at baseline and again at 24 months following intervention. Ergometer resistance was ramped until participants reached 70% of age-predicted maximal heart rate, after which resistance was clamped for a 3-minute period. Endurance fitness was measured as average power output in watts (W) during the 3-minute period. This measure has a reproducibility coefficient of 85%, based on 58 independent test-retest trials in these participants. In all, 82% of 225 participants tested to date increased on endurance fitness at 24 months (P < 0.001). This percentage varied little by gender or age (≤ 50 y and ≥ 50 y). Mean ± SD endurance fitness was 80.3 ± 35.3 W at baseline and was 93.1 ± 38.4 W at 24 months. Participants in PRIME G increased 13.4 ± 15.6 W, those in PRIME C increased 12.4 ± 15.7 W, and those in PRIME SC increased 12.2 ± 15.5 W from baseline to 24 months (P < 0.001 each). ANCOVA showed that after adjustment for age, gender, ethnicity, cohort, and baseline value, there were no significant differences across treatments in endurance fitness at 24 months. We conclude that the Group- and Correspondent Lifestyle interventions were equally effective in increasing endurance fitness over 24 months, while Standard Care controls may also have benefited from lifestyle counseling in their YMCA programs. Supported by NIH HL 58608

Challenges and opportunities for measuring physical activity in sedentary adults.

Increasing the physical activity of typically sedentary adult populations is at the forefront of the public health agenda. This review addresses the challenges in defining and measuring physical activity in this target group, for a number of purposes, namely, scientific or academic inquiry, surveillance, clinical application and programme evaluation. First, we clarify the conceptual distinctions between the terms sedentarism, physical inactivity, physical activity and energy expenditure. Next, we review and compare the utility of different approaches for quantifying and expressing physical activity in these populations. Physical activity in typically sedentary populations is most likely a simple pattern of behaviour that has been largely obscured by existing measures and its expression as energy expenditure. Existing self-report methods are practical, but suffer from floor effects and recall bias. Walking, the most important activity to assess in this target group, is very difficult to measure through self-report methods. Motion sensors are more appropriate for quantifying physical activity behaviours in typically sedentary populations. Of the 2 types of motion sensors - the accelerometer and the pedometers--the latter is more appealing because it is both an affordable and a 'good enough' measure of physical activity, specifically ambulatory activity. Although a common measurement approach would greatly facilitate our understanding of physical activity behaviour patterns, the selection of an approach ultimately depends on the purpose of the study and to a great extent, its budget. Researchers, clinicians and practitioners interested in accurately capturing the lower end of the continuum of physical activity (that is characteristic of sedentary populations) must thoughtfully consider the relative advantages and disadvantages of the available approaches.

Challenges Faced in Recruiting Patients from Primary Care Practices into a Physical Activity Intervention Trial

Background. Special challenges are encountered when clinical trial recruitment targets a physician practice-based population, as opposed to recruiting from the community. Since most published information about recruitment has focused on the latter group, summation of successful primary-care-based recruitment strategies could prove useful for future trials recruiting from this population.Methods. The Activity Counseling Trial (ACT) is a multicenter, randomized clinical trial that evaluated approaches to primary care-based interventions to increase physical activity in sedentary adults 35–75 years of age. Fifty-four clinicians from eight practices recruited 874 participants from three U.S. sites. Recruitment challenges that related, in great part, to the primary care setting included: (1) focusing on patients from ACT physician practices who had regularly scheduled or intend-to-schedule appointments within the next year; (2) placing trial staff in the clinical offices for recruitment purposes; and (3) placing trial interventionists in the physicians' offices. Other challenges were related to recruitment of minorities and men.Results. Patient mailing yielded 43.4% of all randomized participants, followed by office-based questionnaires (32.5%) and direct telephone contact (21.6%). Based on a retrospective cost-effective analysis (indirect costs excluded), the self-administered office-based questionnaire was the least costly strategy for one site ($14/randomized participant), followed by patient mailing at another site ($58). The direct telephone contact method utilized at one site serving primarily a minority population yielded a per randomized participant cost of $80.Conclusions. Recruitment of clinical trial participants from practice-based populations requires modification of the strategies used to recruit from the community. Multiple strategies should be employed, followed closely for their respective yields, and adapted as needed.

18 Challenges faced in recruiting patients from primary care practices into a behavioral modification trial

The Activity Counseling Trial (ACT) is a multicenter, randomized clinical trial that is evaluating a primary care-based intervention to increase physical activity in sedentary adults aged 35-75 years old. Eight primary care practices with a total of 54 clinicians (51 physicians. 2 physician assistants and 1 nurse practitioner) are recruiting 810 participants within three U.S. clinical sites. ACT has encountered a variety of recruitment challenges that relate, in great part, to the primary care setting. These include: 1) limiting the target population to patients having regularly scheduled or intend-to-schedule appointments with ACT physicians within the next year; 2) timing randomization into the trial to coincide with the patient’s next physician appointment; 3) involving primary care physicians and their staff, who receive little or no monetary support for the study; and 4) placement of the trial interventionists (2 per clinical site) in the primary care physicians’ offices. Special challenges have also been faced in recruiting males and minorities into the study. Summation of successful (and unsuccessful) ACT recruitment strategies could prove useful for future trials recruiting patients from primary care practices. Strategies employed in ACT include use of office-based questionnaires. creation of mailing lists from patient databases/appointment lists/chart reviews, addition of Physician Assistants and Nurse Practitioners to increase the ACT “cat&rent” population, establishment of incentives for physicians/nurses/staff, inclusion of more physicians and more practices, and examination of the recruitment potential among various types of practices [e.g.. university affiliated, high socioeconomic status (SES) and low SES].

Project Active: A Randomized Clinical Trial of Lifestyle and Structured Physical Activity Programs 428

The purpose of this symposium is to discuss the 24-month primary and secondary outcomes of Project Active. Project Active is the first long-term randomized clinical trial that compares Lifestyle with Structured gymnasium-based approaches to increasing physical activity in sedentary adults. In this study, 235 men and women between the ages of 35 to 60 years were randomized into either a Lifestyle physical activity program or a traditional Structured gymnasium-based program. Primary outcome measures for the study were physical activity and aerobic power. Secondary outcome measures include blood pressure, cholesterol, percent body fat, body mass index, and psychosocial measures. The design and statistical analyses of the study will be discussed by Harold W. Kohl, III and James B. Kampert. The intervention methods will be described by Andrea L. Dunn. Bess H. Marcus and Melissa E. Garcia respectively will discuss the psychosocial results and the main findings. Finally, Steven N. Blair will summarize what we have learned and lead the final discussion on what direction future efforts should take.