The first time Troy Williams tried Total Resistance Exercise (TRX) training, he definitely felt the results the next day.

The longtime martial arts instructor and fitness trainer had done a session of suspension training more than six years ago, repeatedly pulling against large straps attached to a wall in different ways for about a half hour. In theory, it didn’t sound like much of an exercise to Williams. In practice?

“I couldn’t move the next day,” he said. “I said, ‘Oh my goodness, this is awesome.’ Nothing kicked my tail like that at all.”

That’s why Williams became a certified TRX trainer, and it’s why he brought TRX to his local gym, Impact Martial Arts & Fitness, inside Oak Park Mall in Austin.

At its core, TRX allows people to use their own body weight as resistance while doing a series of calisthenics. There are push-ups, running exercises, stretches, crunches and more that can be done with a suspension strap at TRX class. Because the exercises feel so intense, a TRX class is only a half-hour long.

“The cool thing is anybody, anybody, from a house mom to an elite athlete can come in and do TRX, and it can challenge the elite of the elite,” Williams said. “I have professional athletes that I train with it, and house moms who have lost inches off the waist.”

TRX is quite popular at Williams’ other gym in Edina, and the word is out among Austinites on how punishing, yet satisfying the class can be.

“[I hear it] pushes your limitations,” said Katie Lowe, who decided to start class last week.

Several participants who joined her said TRX was a great way to push themselves, especially when it comes to training the core.

“It works your muscles in a different way,” Kaye Hansen said. Though Hansen also has a YMCA of Austin membership, she said she enjoyed coming to TRX as well.

“It’s a really good workout,” she said. “The first time I did it, my arms were like Jell-O for three days.”

The Austin Bruins may feel the burn this summer, as Williams said he’s in talks with the Bruins to provide TRX sessions over the summer and fall. Bruins players may be in for a tough time, however.

“The cool thing about it is you can do over 500 different exercises,” Williams said. “While you’re in different positions, you’re always engaging your core muscles. It increases your muscular endurance, it benefits people of all fitness levels, from athletes to seniors.”

Impact offers TRX classes on Thursdays, Fridays and Saturdays by appointment only. Williams said TRX classes are held for half-hour intervals from 11 a.m. to 4:30 p.m. Thursdays, all day long on Fridays — beginners are encouraged to attend on Fridays — and 10:30 a.m. to 1:30 p.m. on Saturdays.

Residents may want to call soon, as classes are filling up based on recommendations.

“The more you do it, the more your muscles improve in strength,” Hansen said.