Like your short-sighted dog, most fitness trackers are a bit 'ballpark' when it comes getting an idea of your specific movements. Sure, Fitbit's SmartTrack has an uncanny ability to tell that you're cycling rather than running, but what about logging that kettlebell session you've just struggled through? For telling these apart from side-lying leg lifts you ideally need a wrist tracker that works with a foot pod. That's the idea behind the Biostrap ($249), which also claims to be a next-gen health tracker thanks to a pulse oximeter for capturing both heart-rate variability and oxygen saturation. With waterproofing for swim-tracking and a five-day battery life, it might just be the beefcake that knocks the Fitbit off the top of the gym leaderboard.