There’s a reason why our students become raving barre maniacs—and it’s not because they look pretty doing a plié.

Rather, barre is revolutionizing bodies in an all-new way, and it’s thanks to two little words:

One inch.

That’s right, one inch is all it takes to completely overhaul your physique in a way that doesn’t require heavy lifting, heavy grunting, heavy barbells, and heavy weights. Who knew?

See, when you come to a barre class, you’ll be moving your body through a full range of movements and isometric holds, leading into what’s called “pulsing,” which means that you’ll be isolating a muscle group—say, your glutes—and, through a series of micro-movements of just one inch, you’ll exhaust the muscle and force it to change its shape. This is called eccentric training—we keep the energy costs low, while keeping the force/exertion high. This leads to muscles that respond dramatically differently than traditional weight lifting methods, because you aren’t moving the muscle as a whole; you’re isolating individual slow twitch muscle fibers.

And that’s the second set of the two most important words in this practice:

Muscle. Fibers.

The more you focus on a micromovement, the more you recruit your muscle fibers—and that leads to revolutionary new changes, fast. Ultimately, the muscle is loaded negatively (the weight is more than the force the muscle is generating) thus lengthening it under resistance. And that’s what we call gravity-assisted lengthening, otherwise known as eccentric.

You benefit from the pulsing, but also from the holding of a posture, in which you’re continuously engaging the muscle in a different way. However, you’re also getting a mini-recovery with each pulse, so you can hang even longer—and get an even better workout.

This is one reason there’s less damage than traditional strength training methods—and why barre also results in faster muscle recovery. It’s all about those slow twitch mini muscle fibers—and the way we ask them to perform mini-movements. We’re able to strengthen and lengthen muscles without straining tendons or ligaments.

As a bonus? This type of training has been shown to increase the secretion of muscle-building hormones, like HGH and testosterone, compared to conventional methods, according to a 2007 Journal of Strength and Conditioning Research study.

As they say: why work harder when you can work smarter?

For decades, devotees have flocked to barre, obsessed with the changes that were clearly taking place on their physique.

Now there’s proof that it wasn’t mere serendipity, but science.

How will you re-engineer your body shape today?

NEXT: The Top 10 Ways Barre is Raising the Bar

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