This paper explores physical activity adherence among older adults in clini
cal research. We address the unique challenges associated with promoting ph
ysical activity, including the amount of time and effort, perceived benefit
s, and recommendations from professionals. We explore useful strategies to
enhance adherence in the realm of physical activity interventions, includin
g the development of theory-based physical activity interventions that ackn
owledge participant needs and expectations, promote self-regulatory skills,
view exercise as an ongoing process subject to relapse, and utilize phone
contacts for home-based activity programs. We conclude with directions for
future clinical trials to enhance exercise adherence that include the need
for a precise definition and operationalization of adherence, linkages betw
een physical activity interventions and theory, and the study of exercise i
n both structured and home-based settings. Control Clin Trials 2000;21:212S
-217S (C) Elsevier Science Inc 2000.