The purpose of this study was to examine the feasibility and preliminary efficacy of a theory-driven and a atheoretical reminder point-of-choice (PoC) prompt interventions on reducing workplace sedentary behavior in office workers with self-reported low usage (<4 hours per day) of their sit-stand workstations in the standing position. The design of this study was a cross-over trial including randomization into either the theory-driven or atheoertical reminder condition, after completion of a no prompt control condition. Participants (N=19) included full-time, primarily female, Caucasian, middle-aged office workers. The primary aim of this study was to assess the feasibility of these two PoC prompt conditions on reducing sedentary behaviors through the use of a Therapy Evaluation Questionnaire. The secondary aim of this study was to assess the preliminary efficacy of the two PoC prompt conditions on reducing sedentary behaviors relative to no-prompt control using the activPAL micro device. For the primary aim, descriptive means adjusted for ordering effect were computed. For the secondary aim, mixed-effects regression models were used to cluster for observations within-persons and were adjusted for age, gender, race, job-type, and ordering effects. During the no-prompt control, participants spent 267.90 ± 68.01 sitting and 170.20 ± 69.34 min/8hr workday standing. The reminder PoC prompt condition significantly increased sanding time (b[se] = 24.52 [11.09], p=0.034) while the theory-driven PoC condition significantly decreased time spent in long sitting bouts b[se] = -34.86 [16.20], p=0.036), both relative to no prompt control. No statistically significant reductions in sitting time were seen in either PoC prompt condition. Furthermore, no statistically significant differences between the two PoC prompt conditions were observed. This study provides feasibility insight in addition to objective measures of sedentary behaviors regarding the use of PoC prompt interventions in the workplace.

Having accurate measurements of sedentary behaviors is important to understand relationships between sedentary behaviors and health outcomes and to evaluate changes in interventions and health promotion programs designed to reduce sedentary behaviors. This dissertation included three projects that examined measurement properties of wearable monitors used to measure sedentary behaviors. Project one examined the validity of three monitors: the ActiGraph GT3X+, activPAL™, and SenseWear 2. None of the monitors were equivalent with the criterion measure of oxygen uptake to estimate the energy cost of sedentary and light-intensity activities. The ActivPAL™ had the best accuracy as compared with the other monitors. In project two, the accuracy of ActiGraph GT3X+and GENEActiv cut-points used to assess sedentary behavior were compared with direct observation during free-living conditions. New vector magnitude cut-points also were developed to classify time spent in sedentary- and stationary behaviors during free-living conditions. The cut-points tested had modest overall accuracy to classify sedentary time as compared to direct observation. New ActiGraph 1-minute vector cut-points increased overall accuracy for classifying sedentary time. Project 3 examined the accuracy of the sedentary sphere by testing various arm elevation- and movement-count configurations using GENEActiv and ActiGraph GT3X+ data obtained during free-living conditions. None of the configurations were equivalent to the criterion measure of direct observation. The best configuration of the GENEActiv was: worn on the dominant wrist at 15 degrees below the horizontal plane with a cut-point <489 for each 15-second interval. The best configuration for the ActiGraph was: worn on the non-dominant wrist at 5° below the horizontal plane with a cut-point of <489 counts for each 15-second interval. Collectively, these findings indicate that the wearable monitors and methods examined in this study are limited in their ability to assess sedentary behaviors and light intensity physical activity. Additional research is needed to further understand the scope and limitations of wearable monitors and methods used to assess sedentary behaviors and light intensity physical activity.

Physical activity is critical for optimal health and has emerged as a viable option to improve sleep. Moderate- and vigorous-intensity physical activity comparisons to improve sleep in non-exercising adults with sleep problems is limited. The purpose was to determine the effects of moderate- or vigorous-intensity exercise on sleep outcomes and peripheral skin temperature compared to a no-exercise control. The exercise intensity preference also was determined.

Eleven women (46.9±7.0 years) not participating in regular exercise and self-reporting insomnia completed a graded maximal exercise test followed by a crossover trial of three randomly assigned conditions separated by a 1-week washout. Participants performed moderate-intensity [MIC, 30 minutes, 65-70% maximum heart rate (HRmax)] or high-intensity (HIT, 20 minutes, 1-minute bouts at 90-95% HRmax alternating with 1-minute active recovery) treadmill walking or a no-exercise control (NEC) on two consecutive weekdays 4-6 hours prior to typical bed time. A dual-function wrist-worn accelerometer/temperature monitor recorded movement and skin temperature from which sleep-onset latency (SOL), sleep maintenance, sleep efficiency, total sleep time (TST), and peripheral skin temperature changes were calculated. Participants self-reported sleep outcomes weekly, enjoyment of exercise the morning after HIT and MIC, and exercise intensity preference upon completing all conditions. Mixed models analysis of variance examined differences between and within conditions controlling for demographic characteristics and habitual physical activity.

HIT resulted in up to a 90-minute TST increase on night four (448 minutes, 95% CI 422.4-474.2) compared to nights one-three. MIC nights three (43.5 minutes, 95% CI 30.4-56.6) and four (42.1 minutes 95% CI 29.0-55.2) showed nearly a 30-minute SOL worsening compared to nights one-two. No other actigraphy-measured sleep parameters differenced within or between conditions. Self-reported sleep outcomes, peripheral skin temperature change, and exercise enjoyment between conditions were similar (p>0.05). More participants preferred lower (n=3) to higher (n=1) intensity activities.

Early evening high-intensity and moderate-intensity exercise had no effect on sleep outcomes compared to a control in non-exercising adults reporting sleep complaints. Sleep benefits from HIT may require exercise on successive days. Participants indicated partiality for lower intensity exercise. More information on timing and mode of physical activity to improve sleep in this population is warranted.

Background: Limited physical activity (PA) is a key factor contributing to obesity and independently protects from diseases in youth and later in life. Students spend most of their time in schools sedentary and have limited opportunities to engage in PA. By making changes to the school environment and developing a school culture that actively supports and reinforces PA behavior, Comprehensive School Physical Activity Programs are designed to make PA engagement throughout each school day the accepted social norm. The purpose of this study was to determine the effects of environmental and behavioral modifications to school-level PA participation for girls and boys.

Methods: This study used a hybrid reversal design by alternating baseline phases with two intervention phases that provided increased access and opportunity to PA, and behavioral prompting and reinforcing plus access and opportunity, for all students to engage in PA during lunch. Physical activity and contextual data were collected using a previously validated instrument (System for Observing Play and Leisure Activity in Youth; SOPLAY). Behavioral data were collected using a novel instrument (System for Observing Behavioral Ecology for Youth in Schools; SOBEYS) developed to measure prompting and reinforcement contingencies of PA participation consistent with the Behavioral Ecological Model.

Data Analysis: The number of students engaged in moderate-to-vigorous PA (MVPA) and the proportion of students in MVPA were analyzed using visual analysis of graphic data and general linear statistical models, with environmental and behavioral variables as predictors.

Results: Increases in the number of girls and boys in MVPA were seen visually and statistically during the environmental and the environmental plus behavioral intervention phases compared to baseline. No differences were seen visually or statistically between intervention phases. Intervention effects were larger for boys than girls. The SOBEYS instrument was able to produce valid and reliable data regarding prompting and reinforcement of PA. However, environmental factors appear to have a greater influence on PA than behavioral factors.

Conclusion: Modifying the school environment to increase access and opportunity for PA during lunch can lead to positive changes in MVPA during the school day, with special consideration needed to engage more girls.

The health benefits of physical activity are widely accepted. Emerging research also indicates that sedentary behaviors can carry negative health consequences regardless of physical activity level. This dissertation explored four projects that examined measurement properties of physical activity and sedentary behavior monitors. Project one identified the oxygen costs of four other care activities in seventeen adults. Pushing a wheelchair and pushing a stroller were identified as moderate-intensity activities. Minutes spent engaged in these activities contribute towards meeting the 2008 Physical Activity Guidelines. Project two identified the oxygen costs of common cleaning activities in sixteen adults. Mopping a floor was identified as moderate-intensity physical activity, while cleaning a kitchen and cleaning a bathtub were identified as light-intensity physical activity. Minutes spent engaged in mopping a floor contributes towards meeting the 2008 Physical Activity Guidelines. Project three evaluated the differences in number of minutes spent in activity levels when utilizing different epoch lengths in accelerometry. A shorter epoch length (1-second, 5-seconds) accumulated significantly more minutes of sedentary behaviors than a longer epoch length (60-seconds). The longer epoch length also identified significantly more time engaged in light-intensity activities than the shorter epoch lengths. Future research needs to account for epoch length selection when conducting physical activity and sedentary behavior assessment. Project four investigated the accuracy of four activity monitors in assessing activities that were either sedentary behaviors or light-intensity physical activities. The ActiGraph GT3X+ assessed the activities least accurately, while the SenseWear Armband and ActivPAL assessed activities equally accurately. The monitor used to assess physical activity and sedentary behaviors may influence the accuracy of the measurement of a construct.