Factors predicting gains in moderate-to-vigorous physical activity in prostate cancer survivors on androgen deprivation therapy.

Background: Whether individual, environmental, and psychosocial factors predict changes in moderate-to-vigorous physical activity (MVPA) is poorly addressed in prostate cancer (PC) survivors undergoing androgen deprivation therapy (ADT).

Purpose: This secondary analysis of a randomized controlled trial examined changes in MVPA following a supervised personal training (PT), supervised group-based (GROUP) program, or a home-based, smartphone-assisted exercise (HOME) intervention in PC survivors on ADT and explored individual, environmental, and psychosocial predictors of MVPA.

Methods: PC survivors on ADT underwent aerobic and resistance training for 6 months via PT, GROUP, or HOME. MVPA was captured via accelerometers and the Godin Leisure-Time Exercise Questionnaire. Changes in MVPA between groups were assessed using linear regression. The following predictors of MVPA were examined using Spearman correlations: the Neighborhood Environment Walkability Scale (NEWS); the Planning, Attitudes, and Behaviours (PAB) scale; the Relatedness to Others in Physical Activity Scale (ROPAS); and individual factors at baseline.

Results: Participants (n = 37) were 69.4 ± 6.5 years old and 78.4% were on ADT for ≥ 3 months. Changes in accelerometry-based bouts and MVPA as well as self-reported MVPA did not differ between groups at 6 months. The Aesthetics domain of the NEWS questionnaire at baseline was the strongest predictor of positive MVPA changes (r = .66). Attitude (r = .64), planning (r = .57), and motivation (r = .50) at baseline were also predictive of engaging in higher MVPA throughout the intervention.

Conclusion: Changes in objective MVPA were modest. Additional emphasis on specific psychosocial and individual factors is important to inform theory-based interventions that can foster PA behavior change in PC survivors on ADT. Registration # NCT02046837.