Washington, Aug 21: Jennifer Lopez has offered some valuable tips to new mothers to get back in shape.

The 'Waiting For Tonight' hitmaker insisted that the gruelling effort of triathlon training is worth the results.

She gave birth to twins Emme and Max on 22 February 2008 and has since been preparing to take part in the endurance sports like swimming, cycling and running to bounce back into shape.

"You've got to start slow and give yourself time. This is not something that is natural to me but it's something that is a challenge," Contactmusic quoted her, as saying.

"I'm always into challenging myself and seeing what I can do. You have to start little by little and you just work up to it.

"The swimming is a killer, I'm not going to lie. I'm not a natural swimmer," she said.

"(Swimming is) very foreign. I'm a good athlete - I feel like my stamina. I can get it up there if I work really hard but ... the swimming is a killer (Olympic swimmer Michael) Phelps - he has nothing on me," she added.

ANI