Here is an example of a lighter resistance circuit you can do to tone up without adding bulk. (rachaelattard.com)
The sprint is at the very end of the circuit, after you've already completed an intense bodyweight resistance circuit. (liftingrevolution.com)
Along the same lines, if you're plateaued with fat loss, you should definitely do resistance circuits — multiple rounds of timed exercises with short rests. (workoutnirvana.com)