Dust Off Your Old Rollerblades for This Calorie-Torching 20-Minute HIIT Workout

Remember the Rollerblades you stashed in your garage or closet in the '90s ​just in case​ you ever wanted to use them again? Well, today is the day you dig them out.

The in-line skating you did way back when may have been more on the easygoing side of the fitness spectrum, but this blast-from-the-past workout is designed to burn maximum calories in minimal time — and it's a safe way to spend some time outside when you're stuck at home.

The 20-minute Rollerblading routine below takes the shape of a high-intensity interval training (HIIT) workout. Alternating between periods of hard work and short periods of rest is an extremely time-effective way to burn calories, according to a March 2014 study in ​Applied Physiology, Nutrition and Metabolism​. In fact, in just 20 minutes of Rollerblading, a 155-pound person can burn around 175 calories, according to Harvard Health Publishing.

Plus, you might find HIIT workouts more enjoyable than steady-state training like 30-minute jogs or walks. In a small July 2016 study in ​PLOS One​, for example, women rated HIIT cycling workouts as more fun than cycling continuously at the same speed. Bonus: You're more likely to stick with a fitness routine you actually enjoy.

Before you lace up your blades, get your body ready for exercise with 3 rounds of the following:

• 10 jumping jacks
• 10 forward folds (reach to the sky and then reach toward your toes)
• 10 arm circles forward
• 10 arm circles backward

This 20-minute HIIT Rollerblading workout is a classic Fartlek session. "Fartlek" is a Swedish term that means "speed play" — not a made-up word. Structuring your HIIT workouts this way can help you improve both your speed and endurance. You'll work continuously for a set period of time — in this case, 20 minutes — with speed changes throughout.

An ​easy pace​ means you should be able to talk freely while skating. Your heart rate should only feel slightly elevated, and you should be able to control your breathing.

A ​moderate pace​ should make it difficult, but not impossible, to talk. You may only manage a couple words at a time, and your breathing will be heavier.

A ​fast pace​ means you're working hard, but you should still feel like you can keep going after the interval is up. You probably won't be able to talk. You should be taking long strides on your skates and starting to feel a burn in your muscles.

A ​sprint pace​ is an all-out effort. You definitely won't be able to talk and your heart will be pounding. You may get significantly winded — but you can do this!

Once you complete the 'blading circuit, slow it down with an additional five minutes of skating at an easy pace. You can also opt to take your Rollerblades off and walk instead. Then flow through a few of the best stretches for your legs to minimize the risk of post-workout soreness.