Carrie Underwood is the picture of fitness. Her legs are quite the envy in country music circles, and her trainer, Erin Oprea, is the one to thank. She shared a photo of the singer in action, proving Underwood spends as much time on her upper half as she does her lower.

The singer is hanging from a pull-up bar, wearing shorts and a black tank top, and as Oprea captions, "Check out @carrieunderwood killin it on her pull-ups today!! Awesome job!" One look at Underwood and fans everywhere will be motivated to hit the gym.

The main reason for Underwood's relationship with the trainer is for general fitness. Oprea, says, "She wanted to tone up and not get winded while singing and dancing." With songs like 'Two Black Cadillacs' and 'Blown Away' that require powerhouse vocals and lots of stamina, Underwood's workouts are obviously paying off; she always sounds good on stage, and continuously makes a splash on the red carpet.

Oprea previously told Glamour that Underwood is a huge fan of the cherry picker workout move, which are a strong force behind her powerful legs. But, there's also a secret to her super sculpted arms. Oprea shares, "She loves all different leg exercises! Most females dislike pull-ups, but it is a very important exercise in toning your upper body."

"Carrie is amazing to work with. We have a lot of fun," says her trainer. "Carrie always brings it! She is a real person ... I don't think of her as a celebrity. We have a true working relationship that has developed into a friendship. She is hard worker, motivated and disciplined."