Professional sport in the United States has widely adopted biometric technologies, dramatically expanding the monitoring of players’ biodata. These technologies have the potential to prevent injuries, improve performance, and extend athletes’ careers; they also risk compromising players’ privacy and autonomy, the confidentiality of their data, and their careers. The use of these technologies in professional sport and the consumer sector remains largely unregulated and unexamined. We seek to provide guidance for their adoption by examining five areas of concern: validity and (...) interpretation of data; increased surveillance and threats to privacy; risks to confidentiality and concerns regarding data security; conflicts of interest; and coercion. Our analysis uses professional sport as a case study; however, these concerns extend to other domains where their use is expanding, including the consumer sector, collegiate and high school sport, the military, and commercial sectors where monitori... (shrink)