Texting to Increase Adolescent Physical Activity: Feasibility Assessment.

Objective: Feasibility trials assess whether a behavior change program warrants a definite trial evaluation. This paper reports the feasibility of an intervention consisting of Self Determination Theory-informed text messages, pedometers, and goal prompts to increase adolescent physical activity.

Methods: A 4-group randomized design with baseline and immediate post-study assessments was used. Groups (pedometer; pedometer + goal prompt; pedometer + goal prompt + theory-informed texts; no-treatment control) were systematically varied to assess the additive effect of intervention components on objectively measured physical activity (ie, ActiGraph). The primary outcome of the 12-week intervention was program feasibility. Changes in average daily step counts and minutes of moderate-to-vigorous physical activity also were examined. Post-intervention research with a subset of participants examined program reactions.

Results: Participants (N = 160) were evenly split by sex, mostly 14-15 years old, and of diverse race/ethnicity. Feasibility criteria were met. The attrition rate was less than 2%. Modest increases in average daily step counts and moderate-to-vigorous physical activity were observed in all groups except the control group. Participants reported positive reactions to the intervention.

Conclusions: An intervention consisting of pedometers, theory-informed texts, and goal prompts, is a feasible and acceptable method for promoting physical activity to adolescents.