Smart Walk: A Culturally Tailored Smartphone-Delivered Physical Activity Intervention for African American Women

Participants will wear wrist-worn ActiGraph GT9X Link Activity monitors the activity monitor on their non-dominant wrist during all waking hours for 7 consecutive days to provide an assessment of usual activity

Assessed by the 7-Day Physical Activity Recall

A modified Balke treadmill protocol will be used to estimate maximal aerobic capacity (i.e., VO2 peak).

A measure of aortic stiffness and will be assessed using SphygmoCor XCEL system using validated methodology.

Measured in kilograms using an electronic scale

Calculated using the formula: weight (in kilograms) / height (in meters)squared

Measured in centimeters

Both systolic and diastolic blood pressure will be assessed using electronic sphygmomanometer following 5-min rest

Measured in serum using a commercial multiplex immunoassay platform; blood will be drawn after a 10 hour fast.

Measured in serum using a commercial multiplex immunoassay platform; blood will be drawn after a 10 hour fast.

Measured in serum using a commercial multiplex immunoassay platform; blood will be drawn after a 10 hour fast.

Measured in serum using a commercial multiplex immunoassay platform; blood will be drawn after a 10 hour fast.

Plasma glucose assessed after a 10 hour fasting blood draw. Measured using an automated chemistry analyzer.

Serum insulin collected after a 10 hour fasting blood draw.

Triglycerides, total cholesterol, LDL-C, and HDL-C will be assessed

Assessed by calculating homeostatic model assessment (HOMA) scores as: glucose (mg/dl) x insulin (μU/ml)/405.

Assessed by the 12-item Exercise Self-Efficacy survey (Sallis et al.1987). The range of possible scores for this measure is 1-5, with higher scores indicating higher levels of physical activity self-efficacy.

Assessed by the 10- item Self-Regulation Scale from the Health Beliefs Survey (Anderson-Bill 2006). This scale assesses the use of behavioral strategies to incorporate physical activity into daily activities (i.e., take stairs instead of elevator, walking instead of driving when running errands). The range of possible scores for this measure is 1-5, with higher scores indicating higher levels of physical activity self-regulation.

Assessed by the Social Support for Exercise survey developed by Sallis et al (1987). This scale assesses social support from family support (10-items, with a possible range of scores from 10-50) and friends (8-items, with a possible score range from from 8-40). Higher scores indicate greater levels of social support.

Assessed using the 9-item Outcome Expectation Scale for Exercise scale, developed by Resnick (2000). The range of possible scores for this measure is 1-5, with higher scores indicating more positive expectancies associated with physical activity engagement.

Assessed using a 6-item scale developed by the research team in previous research. The range of possible scores for this measure is 1-6, with higher scores indicating higher levels of behavioral capability of physical activity.

Survey assessing acceptance, feasibility, and consumer satisfaction of intervention.

Fitbit wear, app utilization, and adherence to physical activity coaching session protocols will be assessed as moderators.

Costs borne by the program, including Fitbit activity monitors, Smart Walk app development, and all personnel salaries/hourly wages.

Participant costs associated with study participation, including time spent using the Smart Walk app, time spent in physical activity coaching, and cellular phone data charges over their plan limit.

Cost effectiveness will be evaluated by combining the mean total cost per participant with effectiveness (baseline to 12-month changes in minutes/week of moderate-to-vigorous physical activity). We will calculate the incremental cost effectiveness ratios (ICER) for the Smart Walk intervention compared to the Fitbit comparison arm.

GIS mapping and computer vision techniques will be used to assess macro-scale and micro-scale home neighborhood environment characteristics of participants.

Subjectively-measured Neighborhood Environment Walkability will be measured using the Neighborhood Environment Walkability Scale (NEWS). This measure includes 43 items and assesses the following environmental characteristics: residential density (6-items, possible range of scores range 1-5), land use mix-diversity (22 items, possible range of scores range 1-5), street connectivity (2 items, possible range of scores range 1-4), walking/cycling facilities (6 items, possible range of scores range 1-4), aesthetics (4 items, possible range of scores 1-4), pedestrian/traffic safety (3 items, possible range of scores 1-4). Higher scores indicate greater walkability.

Race-related stress, as a result of experiencing individual, cultural and institutional racism, will be assessed using the 22-item Index of Race-Related Stress-Brief survey. This survey has a possible score range of 0 to 88, with higher scored indicating greater stress as a result of experiencing racism.

Structural racism will be assessed using the 20-item Perceived Structural Racism Scale. This scale has a possible scoring range of 20-120 with higher scores indicating greater levels of perceived structural racism.