I teach spin classes in a gym setting, so I probably sound biased when I say that in-person exercise classes offer indisputable benefits over at-home workouts—but I don't think I'm overstating things.

The company is collaborating with the companies behind the hockey-masked killer to light a fire under your next workout.

The fitness equipment company Peloton is proposing something different: an artificial intelligence-powered camera that detects your movements and gives you real-time feedback while you workout.