What does “tone up” mean?
When people talk about wanting to tone up, usually they mean they want to have a more defined and sculpted body, and not necessarily bigger muscles. A toned-up body is a slimmer one, with noticeable shape and definition. Toned-up muscles are also firmer and probably a bit bigger than average-think Christian Bale in American Psycho, or Angelina Jolie in Tomb Raider.