Pop star Britney Spears has been working hard like an athlete to have an hourglass body, says her trainer Tony Martinez.
The 31-year-old mother of two, who is all set to release her new video, recently posted a sizzling photo of herself wearing only a bikini, reported E! Online.
"She's been a terror lately, working as hard as she can. She's using all sports right now to get ready for her 90 minute Las Vegas show.
"She is doing Olympic-style training. This is hard-core stuff. Britney knew she needed to step up her game. She is just drilling it but she likes too! She loves to sweat and she still talks smack to me," Martinez said.
The Grammy award-winning singer's trainer said though her workouts are less than an hour, they are gruelling.
"It is intense, interval training to keep her heart rate up. In a show, she will be dancing and singing non-stop. In her training, she only has about 10 to 15 second rests between each set," Martinez added.
