As a trainer to stars like Heidi Klum and other Victoria's Secret models [1], Andrea Orbeck [2] knows how to whip a body into shape. If you're looking to step up your shape-up game, this 30-minute cardio interval plan she shared with us is a great way to boost the fat burn and tone the lower body.

The workout is simple — after a four-minute warm up, repeat the interval portion for what Andrea calls amazing "booty-lifting and metabolism-revving benefits." End with a cooldown and 10 minutes of stretching to soothe your muscles. Don't be discouraged if the speed you choose for your high-intensity intervals becomes too hard as the workout progresses. "If the two minutes becomes too hard to maintain, you can always lessen the intensity, lower the level or speed," Andrea suggests. "Over time, you will develop more conditioning and may even challenge yourself to a higher-intensity two minutes!"

Note there aren't speeds in the chart below; use the rate of perceived exertion [3] (RPE) column to determine your speed. Here are some more guidelines for each cardio section:

• Warmup/cooldown: walking or light cycling
• Intense cardio: sprint, fast walking on a treadmill at 15 percent incline, hill sprints, or a challenging level on a bike or elliptical
• Recovery cardio: easy jogging or easy level on a bike or elliptical

*RPE [4] = rate of perceived exertion

End with 10 minutes of stretches for your hip flexors, quads, hamstrings, back, and chest:

• Postrun stretching sequence [5]
• Chest-opening stretch [6]

RELATED: Victoria's Secret Model Workouts [7]