So I've done enough research to find the most popular devices, but have yet to find what I'm looking for. I don't care about anything unrelated to calorie burn. So heart rate monitoring is of top importance, along with whatever other factors you guys know go with that. I do strength training, running, and tennis. I want the most accurate estimation of calories burned. Can anyone point me in the right direction, because every popular device I've looked into has noted the heart rate monitoring etc. isn't great for "real" athletic activity.