This isn’t the first time Spears has showed off her chiseled abs during a sweat session. Earlier this year, she posted a video to Instagram of herself and her personal trainer doing a set of side lunges with weights.
During an interview with Women's Health, Spears admitted that she doesn't like to spend a lot of time in the gym. "I like my workouts to be effective in a short amount of time," she explained. "I start with 20 minutes of intense cardio -- usually running -- move on to light free weights, body-weight exercises such as push-ups, squats and sit-ups, then finish it off with a stretch."
Here's a look at another one of Spears' workout moves.