Defying gravity: Editor-in-chief Kristin Detterline-Munro leans into her training for the TRX equivalent of a pull-up. The training system utilizes the user’s body weight in providing a full-body workout, focused particularly around one’s core.

It all looked simple enough. Take the cushioned handles of two long nylon straps attached to a pull-up bar in each hand, slowly lean back as if sitting in a recliner, and then propel upward and over into a suspended push-up position. "This is called the Superman," said Hector Bones, a personal trainer at The Sporting Club at The Bellevue, as he neatly completed two in a row with perfect form. "Give it a try. I think you can do it."

Motivational speech aside, I sincerely thought I could, too. This was my first tangle with TRX, but it was hardly the first time I had stepped in a gym: In the past 10 years, I had downward-dogged my way through yoga, muscled through four-count push-ups in Pilates, cranked up the resistance dial in spinning, and counted down the minutes on any and every piece of cardio equipment known to man. As far as I was concerned, Superman was about to meet Wonder Woman. But somewhere between the reclining and the propelling, my arms swung out too far and my feet crossed at the ankles, leaving me in a spandex-clad heap at the foot of Bones's sneakers. It seemed only fitting to beg for mercy at that point. "That didn't go so well," Bones chuckled. I laughed, too—having your backside up in the air certainly calls for a moment of levity.

TRX suspension training was invented by Randy Hetrick while he was serving as a Navy SEAL in the '90s. He had no access to a gym, so the straps—at the time, parachute material he hand-stitched together—offered dynamic, challenging full-body workouts that incorporate a variety of movements using nothing more than his own body weight. Over the past few years, the TRX trend has exploded in popularity, first as a home-training system of sorts (à la the Perfect Pushup, founded by yet another SEAL), and then in gyms and fitness clubs across the county.

"There are many benefits to body-weight resistance training," says Dr. Kevin Freedman, a sports medicine specialist who specializes in knee and shoulder injuries at Bryn Mawr's Orthopaedic Specialists. "TRX includes a variety of exercises, so there's core muscle training. People typically go to the gym and do isolated exercises but don't concentrate on larger muscle groups, like the back. This is a more total form of exercise."

Based on my post-workout pain, I can wholeheartedly agree with that statement. My arms felt like jelly, and my quads burned for two days. It wasn't just from the Superman, which ultimately did me in that first day. It was the push-ups that rolled over into pike lifts, and the reclining back rows. Despite the achy aftermath, I tried it again and found that I liked it even more.

TRX has been a popular addition to The Sporting Club's already robust group fitness schedule, with classes available several times a week inside a dedicated TRX studio, where you will find a cross-section of members—both genders, and all ages and fitness levels. On the back of its increasing popularity, The Sporting Club earlier this year introduced TRX/Pilates, a hybrid exercise that draws on key moves from each discipline.

Whether you are sticking with traditional TRX or trying the spin-off, discipline is exactly what you will need to excel. It is a routine that requires some getting used to: keeping your shoulders down, your core tight, your spine elongated while reclining. Even comfortably slipping your feet in and out of the straps takes some time. But the benefits are undeniable: This routine can give you a truly toned physique. I have yet to master the Superman, but that is not a bad thing. In fact, it is keeping me motivated. And no matter the exercise, that is the most important move to master of all. 224 S. Broad St., 215-985-9876