HIIT Workout That's Over in less than 20 fly-right-by minutes

Whether you love it or hate it, the intense stair-climbing machine has been a staple in gyms for decades for a reason. It's effective, because it makes strong legs and a nice backside more than pretty much any other piece of cardio equipment, and it's functional. Let's sweat it out Love Squad: we created a high-intensity interval workout that's over in less than 20 fly-right-by minutes to get in shape for the summer:

THE PRE-ACTIVATION / WARM UP

Before jumping on the machine, a good warm up is key here. Make sure you find an area to complete these two moves, which won't take longer than 3 minutes.

1. Knee Ups: Standing with your feet hip-width apart, bring your knee as close to your chest as possible. Hug and hold your leg for 15 to 20 seconds, then switch sides. Repeat twice.

2. Glute Bridges: Lying on your back, bend your knees so that your feet are firmly planted on the floor, hands by your side. Slowly raise your butt, pushing through your heels, and squeeze your glutes before you release slowly back to floor. That's one rep; do three sets of 10 reps.

THE WORKOUT

0:00-3:00: Warm up at a slow speed, around 3 to 5. Your intensity shouldn't be higher than a 4 or 5 out of 10. 3:00-4:00: Increase speed to 7 or 8. Your intensity should be close to a 7 out of 10—you can talk, but holding a conversation is slightly difficult. 4:00-4:30: Decrease speed to 3 or 4. 4:30-5:00: Set speed to 3, and start skipping a step to mimic a lunge movement. 5:00-6:00: Increase speed to 8 or 9. 6:00-6:30: Decrease speed to 4 or 5. 6:30-7:00: Set speed to 3, and start skipping a step to mimic a lunge movement again. 7:00-8:00: Decrease speed to 1. 8:00-9:00: Increase speed to 7 or 8. 9:00-9:30: Decrease speed to 3 or 4. 9:30-10:00: Set speed to 3, and start skipping a step to mimic a lunge movement. 10:00-10:30: Increase speed to 8 or 9. 10:30-11:00: Decrease speed to 4 or 5. 11:00-11:30: Set speed to 3, and start skipping a step to mimic a lunge movement. 11:30-12:30: Decrease speed to 1 or 2 to cool down.