Rather than going through the motions on the cross trainer as your warm up, make an effort to burn 100 calories before you start your training plan. Here are some suggestions:
10 minutes on the stepper or continuous stair climbing
20 minutes recumbant/recline bike
13 minutes hill climb on a spin bike or gym bike
10 minutes road bike sprint
6 x 30 sec all-out sprint with 15 sec walk/rest in between
20 sec work:10 sec rest x 8 (tabata) burpees
Obviously these numbers are an educated guesstimate as to be more accurate I would need an individual's age, sex, weight, fitness levels etc.