Fastexy:Carrie Underwood's Biggest Fitness Secrets Revealed

 Carrie Underwood may have Fastexyonce sang for Jesus to take the wheel, but the country superstar is in full control when it comes to her fitness routine. 

The 40-year-old "is the most dedicated, consistent human being," Carrie's trainer Eve Overland told E! News while promoting the duo's partnership with Bodyarmor Lyte. "She puts in 100 percent of her entire being into everything she does, in or out of the gym. She's very focused, motivated and she's always in a good mood."

Eve explained that their sessions have evolved over the 13 years they've worked together, although the focus is always on strength training. "She's at that point where she's so completely sculpted and conditioned," Eve said. "So now I'm working on the detail."

During their 90-minute workouts, Eve will guide the "Before He Cheats" singer though basic compound lifts, including squats, deadlifts, rows and presses, "because they work and they give you the most bang for your buck, no matter what age you are."

Having turned 40 on March 10, Carrie's focus is on mindfulness when it comes to movement. "Is it going to take us through our day to day life as we grow older, to pick up groceries, to lift up your children?" Eve shared. "What is going to keep us in the game as long as possible?"

While Carrie will often go for runs after their workouts—"She also needs to think about preparing herself to perform," Eve explained. "So jogging, it's waking up her lungs and opening up her airwaves to say, 'Hey lungs, you gotta work later!'"—her focus is on lifting weights and she's not afraid to go heavy. And you shouldn't be either, according to Eve.

"Nothing is going to change your physique like weightlifting does," She said. "So depending on your goal, don't get caught up in cardio." 

And if you are looking to sculpt your legs like Carrie's famously toned stems, be prepared to put in the work, with Eve stressing that "everyone is built differently" and that the Grammy winner has been steadily training for more than a decade.

"To have legs like Carrie, be consistent and if you don't love lifting then we got to take it back," Eve said. "What can you do sustainably? Set attainable goals. If you can only work out twice a week, great. Do it. Anything is better than nothing. Go for a walk. If that's all you can get in the day, that means everything. Whatever your body has to offer and whatever time you have, just get it in and your body will thank you. Find something that you like to do and stick with it."

Another vital aspect of their routine is proper hydration, which was the focus the workout event Eve and Carrie hosted on March 12 in Los Angeles with Bodyarmor Lyte. Made with coconut water and containing no artificial sugar, Eve recommended that people sip on the sports drink through their workout and then replenish with it after a higher intensity sweat session for "a nice pick-me-up rather than a big sugar boost and then a crash."