5. Jessica Alba 

She got her start playing a genetically manufactured superhuman, so is it any wonder Jessica Alba is still making waves with her hot bikini body? The former Dark Angel star is a busy working mom but still makes time to work in a regular fitness regimen.{relatedarticles}Alba's personal trainer credits the calorie-scorching burpee for helping her stay in shape, while Alba herself has copped to interval training on the treadmill to keep from getting bored while staying hot.