Start out walking slowly for 2 minutes, then gradually pick up the pace to a brisk walk. Switch from using both hands on the stroller to just one. Do large circles with the other arm to warm up your upper body.
Cardio: 5 minutes
As you walk, extend each leg as far forward as possible, without sacrificing form. Occasionally, try pushing the stroller with one hand and swing the other arm alongside your body in the opposite direction as your forward leg.