Physical activity (PA) is an important aspect of behavioral weight loss programs, but the adoption of PA behavior is incumbent on overcoming individual level barriers. It is unclear whether perceptions of barriers change through the course of a behavioral weight loss intervention, or whether the dose of prescribed PA impacts perceived barriers.
Purpose: To investigate the change in perceived PA barriers within a 12-month behavioral weight loss intervention with differing doses of prescribed PA.
Methods: 383 adults with overweight or obesity (age=46.2±7.7 years; BMI=32.1±3.8 kg/m²) were randomized into one of three 12-month intervention groups: Diet alone (DIET, n=127, no prescribed PA); Diet plus Moderate Dose PA (DIET+MOD, n=127, 150 min/week prescribed PA); Diet plus High Dose PA (DIET+HIGH, n=129, 250 min/week prescribed PA). All intervention conditions received the same prescribed diet (1200-1800 kcal/day) and behavioral intervention. Perceived PA barriers were assessed at baseline, 6 months, and 12 months. Barriers were analyzed on a Likert scale (1=strongly disagree; 5=strongly agree) as Total barriers and three subcategories of Time (e.g., too busy), Effort (e.g., lack of motivation), and Obstacles (e.g., family obligations) barriers.
Results: There was significant weight loss in all intervention conditions across the 12-months (DIET=-9.8 kg; DIET+MOD=-10.2 kg; DIET+HIGH=-10.3 kg) (p<0.05). Total barriers to PA decreased significantly across the 12 months (2.67 to 2.44; p<0.0001), with no difference between groups. A similar pattern was observed for obstacle barriers (2.11 to 2.01; p=0.0337). Effort barriers decreased significantly across the 12 months (p<0.001), with a Group X Time interaction (p=0.0133) also observed (DIET: 3.04 to 2.76; DIET+MOD: 3.00 to 2.51; DIET+HIGH: 2.97 to 2.32).
Conclusion: Perceived barriers to PA decreased across a 12-month behavioral weight loss intervention, and this was observed regardless of the amount of PA that was prescribed within the intervention. It does not appear that prescribing a higher amount of physical activity within the context of a behavioral intervention negatively impacts perceived barriers to PA participation. However, time barriers appear to persist, which may have implications for interventions to promotion PA in adults with obesity.