Horrigan, who reveals Jennifer's full Hunger Games workout routine in a new interview with Teen Vogue, stresses that when it comes to fitness, cardio is the foundation. According to Dr. Horrigan, "running, cycling (road, mountain, classes, or simply a regular stationary bike), or various aerobic classes such as dance classes and hiking" will all do the trick, though he reveals that Jen's actual "go-to was skipping."
"Yes, even skipping counts," the magazine confirms.
Though of course, 20 minutes of high intensity cardio following a 5 to 10 minute warm-up isn't all it took to get the 23-year-old in such amazing shape.
Getting Katniss-ready also required lots of strength training that was achieved with high intensity circuit work -- doing exercises including bodyweight squats, push-ups and sit-ups for 30 seconds (or 10 to 15 reps) and then moving on to another.
"If you can do any of these exercises for 20 minutes at high intensity, you will see results," he promises.
Horrigan also suggests trying yoga on less intense workout days, as well as staying consistent with the workouts but still mixing it up to keep your body from plateauing.