The purpose of this paper is to present the rationale , study design , and protocols employed in WalkMore , a 3-arm 3-month blinded and randomized controlled trial ( RCT ) designed to compare the effects of two community pedometer-based walking interventions ( reflecting these separate and combined messages ) relative to a control group on blood pressure in sedentary/low active post-menopausal women , a population at increased risk of cardiovascular disease .