Comparing 3 Goal-Setting Techniques to Promote Adherence to National Physical Activity Guidelines in Midlife Adults: Feasibility Trial of a Mechanistic Study Design.

The study successfully recruited 24 participants in approximately 4 months, achieving an enrollment rate of 6 participants per month.

• Total sample size was n=24
• Mean age was 54.1 years (SD 5.8 years)
• Mean BMI was 36.3 kg/m² (SD 5.0 kg/m²)
• Recruitment was completed in approximately 4 months

Retention at 6 months was 87.5%, with 21 of 24 participants completing the intervention.

• 21 out of 24 participants were retained at 6 months
• Retention rate was 87.5%
• The study was a 6-month Stage IA mechanistic trial based on the National Institute on Aging's Stage Model

Participant engagement with the intervention components was high, with strong attendance at action planning sessions and consistent Fitbit usage.

• Participants completing the intervention attended 85.9% of action planning sessions
• Participants wore the Fitbit for more than 10 hours per day on 87.1% of intervention days
• All participants received a standardized, Social Cognitive Theory-based PA promotion intervention

Data collection rates for outcome measures were very high, ranging from 96% to 100%.

• Outcome measure data collection rates ranged from 96% to 100%
• This supported the feasibility of collecting outcomes necessary for evaluating the effects of different goal-setting techniques in a subsequent larger-scale trial

Participant acceptability of the intervention was high, with most participants expressing satisfaction and willingness to recommend the study.

• 86% (18/21) of participants reported gaining knowledge about physical activity
• 90% (19/21) of participants reported that they would recommend the study to a friend
• Most participants expressed satisfaction with the intervention

The study employed a 4-arm mechanistic trial design comparing three distinct goal-setting techniques against a non-goal-setting comparison condition.

• Group 1: Static Goal-Setting Group with a weekly MVPA goal of 150 minutes
• Group 2: Self-Selected Goal-Setting Group where participants self-selected a weekly MVPA goal
• Group 3: Incremental Goal-Setting Group with a weekly MVPA goal 20% greater than the previous week
• Group 4: Non-Goal-Setting Comparison Group encouraged to increase MVPA without specific reference to a weekly goal
• The only difference across study groups was the goal-setting technique implemented

The study targeted insufficiently active midlife adults with obesity, a population identified as at elevated risk for Alzheimer disease and related dementias due to insufficient aerobic physical activity.

• Engaging in regular aerobic physical activity during midlife is associated with reduced risk for Alzheimer disease and related dementias
• Most midlife adults fail to meet national PA guidelines
• Participants were required to be insufficiently active and have obesity (mean BMI 36.3 kg/m²)