The Unique Exercise That Sculpts Britney Spears' Killer Body

Britney Spears is back in the gym! The 35-year-old mom of two is looking fit as ever these days, as evidenced by her steady stream of workout Instagram pics and videos.

Her most recent fitspiration post shows the singer doing dumbbell work with her trainer offering advice along the way.

My trainer is amazing. She makes working out sooo fun, but always kicks my butt too 😜 Keeps me motivated and grounded... the key to success 🔑

A post shared by Britney Spears (@britneyspears) on

"My trainer is amazing. She makes working out sooo fun, but always kicks my butt too," Spears wrote in the caption. "Keeps me motivated and grounded... the key to success."

Spears tests her strong arms against gravity by doing standing dumbbell presses and lying dumbbell presses followed by another sitting dumbbell press variation. We're guessing her trainer is having Spears add in the sitting, standing and lying down in order to turn the dumbbell presses into compound moves — working multiple muscle groups and joints at once and therefore burning more calories and fat.

MORE: Britney Spears Shows off Sculpted Body in This Fitspo-Worthy Bikini Workout

We don't know about you, but we can't get enough of those abs! We're seriously impressed with Spears' gym time as of late. Earlier this month, Spears motivated the rest of us to break a sweat when she posted a pair of gym selfies showing off an insanely toned bod.

Back at the gym.... stretch and run all the way 💕👙💕💕🌺🌸🎀

A post shared by Britney Spears (@britneyspears) on

Her former trainer Tony Martinez, who according to the Daily Mail trained Spears to get back in shape for her Las Vegas residency, says she'd do "intense" 40-minute workouts three or four times a week.

"She loves all core workouts," Martinez told Daily Mail. "She's a very tenacious woman. She wants to get it done and get it done right."

No wonder her abs are made of steel these days!

Photo Credit: Getty / Jamie McCarthy, Getty / Kevin Mazur