Who she is: A sports nutritionist with a penchant for multitasking
Sample post: This girl shows you how to clean the floor and burn fat at the same time
Why it's useful: The floor cleaning workout may seem ridiculous, but it’s something you can actually do at home, where no one will care about your ridiculousness. Unless you post it on Instagram.
Who he is: Co-founder and president of the World Calisthenics Organization
Sample post: Jumping into the human flag is a bit, uh, aspirational, but still pretty cool.
Why it’s useful: If you thought you needed to bench press hundreds of pounds to build muscle, this guy shows you otherwise with an array of bodyweight exercises.
Who she is: A personal trainer and self-described fitness addict
Sample post: Her “Core Pyramid” will destroy -- then rebuild -- your abs.
Why it's useful: The complete workouts she posts are easy to follow (if not to complete), and usually require no or minimal equipment.