It’s got a name that’s shorthand for the king of dinosaurs, so it’s fitting that this week’s grobby (that’s Greatist lingo for “hobby”) might just be one of the hottest fitness tools since the Cretaceous. Invented by a Navy SEAL looking to stay in shape on missions, it’s now springing up in gyms, homes, and aircraft carriers alike. Yet it’s little more than a nylon strap with some clips and buckles. Meet the TRX.

Slim Gym – The Need-to-Know

No weight plates, no machinery, and no bars: with a price tag around $200, the makers of the TRX (Total-body Resistance Exercise) suspension system claim it’s all we need for killer resistance training. And we’ve already got all the added weight necessary— the human body.

The TRX is comprised of a strap that hangs from a carabineer at its midpoint with two convenient “cradles” (read: stirrups) on either end of a pair of adjustable buckles (the whole thing basically looks like an upside-down Y). The point of the suspension system is to supercharge classic exercises by turning the body into one big cantilever. This forces the core and back into overdrive to stabilize posture, both throughout movement and at rest.

Of course, this kind of stabilization training can be accomplished without suspension— just get into a pushup position and hold a good straight plank. The classic plank has modifications and variations (trainer speak for “easier and harder versions”) that adjust its angle. Planking with hands planted against a wall is great for individuals with less upper-body or core strength. Flipping that stance upside down (feet on the wall, hands on the ground) is an advanced variation for folks who need more.

But there’s that old problem with good walls: they tend to stand still. Stirrups on the ends of straps don’t. The TRX brings the shoulders and hips into the game, too, parts that want to wobble and wiggle and require constant engagement in order to maintain stability.

The TRX opens up entirely new possibilities (not to mention sweet names) for bodyweight training, such as the atomic pushup and body saw pike. Many are basic exercises with an added movement tacked on for increased difficulty, which means fewer reps until exhaustion. The TRX can also make movements easier for those who don’t have the strength for full bodyweight movements. Assisted pullups and assisted lunges are two of many such possibilities, with the only real limit being the imagination.

Getting Strapped – Your Action Plan

There are TRX exercises for all ages and abilities, but as with any new workout, it’s best to start small and with the supervision of an experienced practitioner. TRX classes are offered at gyms across the globe and are great for learning the ropes (see what we did there?) in a fun and safe environment.

A word of caution: those with limited core strength or joint issues might want to be especially careful starting out. Some experts warn that less-fit TRX users might actually cause or aggravate injury by overcompensating and using the wrong muscles to stabilize their bodies.

Ultimately, though, if the ol’ routine just isn’t cutting it, consider adding the TRX as a fun and different physical challenge.

Updated October, 2011