His research examines the effects of sedentary behavior and physical activity on various health outcomes with focus on the workplace. He has conducted studies examining the efficacy of strategies to modify the workplace to be a more active environment and has expertise in using advanced sensor-based measurement techniques to accurately quantify physical activity and sedentary behavior. He has helped develop a wireless multi-sensor integrated measurement system for physical activity. These sensor-based measurement tools help gain a better understanding of the dose-response relationship between health outcomes and physical activity and sedentary behavior. Prior to joining Northeastern University, Professor John was a Post-Doctoral Research Associate in the Kinesiology department at the University of Massachusetts, Amherst.