It’s a type of strength training that uses a special machine to measure the amount of force a person can generate. The machine can have a variable resistance, but it allows people to exercise at a constant speed, regardless of the level of resistance throughout the range of motion.

We recently interviewed Brian Kretsch, trainer and manager at Traverse Fitness, a Ninja Warrior gym in Richmond, California. You’ll find the same daunting (and iconic) obstacles inside Traverse that you’d find on the American Ninja Warrior TV show, from the Warped Wall to the Salmon Ladder.

What’s a heart-healthy way to work up a sweat without it feeling like…well, work? Dancing! Anyone who loves to shake their groove thing, cut a rug, bust a move, or boogie-oogie-oogie will tell you—there’s nothing quite like dance that gives you a workout and immediately reduces your stress