This case study investigated teachers' perceptions and experiences implementing heart rate (HR) monitors in high school physical education (PE) classes. Integrating technology, such as HR monitors, into the classroom influences the way teachers plan, instruct, assess, and motivate students in PE; however, successful integration is dependent upon teachers' knowledge and ability to incorporate this technology successfully. The goal of this research is to create an approach where HR monitors serve as an effective means of instructing, assessing, and motivating students in high school physical education. Guided by three main research questions pertaining to HR monitors: (a) teachers' competency and experiences; (b) teachers' perceived students' motivation; and (c) teachers' assessment practices, 12 high school physical education teachers in Pennsylvania across four focus groups discussed each research question. The results suggest that teachers lacked the training necessary to integrate HR monitors but time, hands-on experience, and collaboration improved teachers' integrative practices; however, integrative practices are inconsistent among schools with what is recommended in the literature. Research focusing on closing the "knowing-doing gap" is needed to understand the practical application of this technology as a means of enhancing students' learning, motivation, and long-term behavioral change. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]