Forget calorie counters, pedometers and the like, the Under Armour Armour39 measures guts. And we don’t mean your beer belly. Using a clever algorithm, the device sees everything, from body position, heart rate to the duration of your train, tots it all up then sends the results to your smartphone revealing just how much – or little – effort you really put into that workout. You have no one to beat, or blame, but yourself.