US$199 ($272), www.stryd.com
STRYD POWER METER
When Craig Alexander, one of the greatest ever Ironman champions, calls this gadget the “next step in the evolution of running,” you’ve got to give it some attention. Created by Princeton engineers, Stryd is the first wearable device to give runners an accurate measure of power. In other words, athletes can accurately measure workout intensity across any terrain, allowing them to see progress and improve efficiency – such as form and technique – whenever they train.