LAUSR

Background Novel strategies to help adults with overweight/obesity increase motivation for becoming active are needed. This single-arm trial aimed to test the feasibility, acceptability, and preliminary efficacy of a 4-h acceptance and commitment therapy (ACT)-based workshop intervention for increasing moderate-to-vigorous physical activity (MVPA) among insufficiently active adults with overweight/obesity. Methods Participants ( N  = 41) received a 1-day 4-h ACT workshop followed by weekly e-mails and monthly phone calls for 3 months. The primary outcome was change in accelerometer-measured MVPA minutes/day at 3 and 6 months. Process variables (i.e., autonomous motivation, PA acceptance) through which the ACT intervention was hypothesized to increase MVPA were assessed via questionnaires. Results Participants completed 91% of phone calls and 75% of e-mail surveys. Acceptability ratings were > 4.5 out of 5 for “understandable,” “useful,” and “intent-to-use” on all intervention components. Participants on average achieved significant increases in bouted and total MVPA at 3 months that were maintained at 6 months. Participants also reported significant increases in physical activity acceptance and autonomous motivation, the latter of which related to MVPA changes. Conclusion Results support the feasibility and acceptability of the ACT workshop intervention for promoting MVPA changes among insufficiently active adults with overweight/obesity. Rigorous testing of this approach as a low-intensity standalone or add-on intervention to increase MVPA is warranted.