Looking at singer Pink on stage rocking out, it's hard to imagine that she just dropped 55 pounds after her first pregnancy. But like most women, Pink was itching to shed the baby weight after giving birth to her daughter Willow more than a year ago. A few months after settling into being a mom, Pink employed not one but two trainers, Jillian Michaels and Jeannette Jenkins, to get her rockstar abs back. "They both kicked my butt more than any other person I've ever worked out with," she tells Shape. "My favorite workout that takes care of the whole body is sprinting, honestly. It's like nothing else." And after losing the weight, Pink claims she's now in the best shape of her life. Head out to the local track and try a round of 100-meter sprints at different speeds like Pink, and that extra weight will melt off!