“…As older adults have more access to cell phones than other technologies and are increasingly using mobile phones and the internet (Anderson & Perrin, 2017;Joe & Demeris, 2013), designing new ways to use these technologies to promote health and physical activity has become an obvious research goal (Gell, Rosenberg, Demiris, LaCroix, & Patel, 2015;O'Reilly & Spruijt-Metz, 2013). Recent studies have shown that texting increases certain domains of self-reported physical activity (Antoine Parker & Ellis, 2016;Kim & Glanz, 2013;Muller, Khoo, & Morris, 2016). For example, Robin et al (2017) showed that guided imagery texts delivered via cell phones were successful at increasing weekly minutes of aerobic physical activity (APA) among older adults, notably by enhancing their motivation.…”