HIIT Was Named The Most Popular Workout 2 Years In A Row. Here's Why It's Not Going Anywhere

It's a new year, but we're carrying one popular 2017 workout straight into 2018. High-intensity interval training—more commonly referred to as HIIT—is No. 1 on the American College of Sport's Medicine fitness list for the second year in a row. Characterized by short bursts of super-intense, heart-pumping movements like sprints, burpees, or jumping jacks, HIIT gained popularity when people discovered that they could get a solid workout in an extraordinarily short amount of time, like 10 or 20 minutes. In an age when we're busier than ever, it makes sense that HIIT is particularly appealing.

HIIT isn't just a timesaver: It also works. "From the heart to the muscles to the metabolic system, all are pushed to the limit, and the body’s response is to function more efficiently," explains Kaiser Permanente's Robert Sallis, M.D.

According to HIIT expert and 12-Minute Athlete founder Krista Stryker, HIIT isn't just great for the person who's too busy to work out. "It's time-efficient, but it also works well as an equipment-free workout, so you can still do HIIT no matter where you are, whether it's outside in a park, your tiny apartment, or a hotel room," she explains. "Plus, it gets results—even just a few HIIT sessions a week will get you stronger, leaner, and in better shape than if you spent double or triple the amount of time doing steady-state cardio."

While there's no question that HIIT is a great workout, Todd McCullough, founder of TMAC Fitness and mbg class instructor, stresses that you should always strive for balance in your workouts.

"People love the adrenaline rush," he says. "Add to the fact we are busy going from one appointment to the next; HIIT allows for a great workout in a short period of time, and that's why HIIT is here to stay."

"That being said, I advocate the yin/yang philosophy with fitness and life," he adds. "You maybe going hard with your HIIT workouts every day and loving it, but if you are serious about being the best you, it’s critical to understand balance. Mix in a yoga flow a few times a week to complement your kick-ass HIIT workouts."

Want to get your HIIT game on ASAP? If you don't want to be bothered with equipment, give Stryker's leg-focused workout below a try—and don't worry if you don't have access to a sunny beach. You can do these in your apartment!

Start in a kneeling position while pulling your shoulders back and bracing your core. Sit back slightly, then thrust your hips as you jump your legs up so that the bottom of your feet are on the ground and your body is in a deep squat position. Immediately do a tuck jump, bringing your knees toward your chest, then step down to the starting kneeling position and repeat.

Start in a squat position with one hand touching the ground. Jump up as high as you can, rotating 180 degrees midair. Land back in a squat position, touching the ground with the opposite hand. Repeat.

Start in a lunge position with your knees touching or almost touching the floor. Without pausing, alternate legs, bringing your opposite leg forward into a lunge position. Continue alternating legs while moving forward.

From standing, squat down and jump as far forward as you can, explosively. Repeat, trying not to pause in between jumps.

Stand in a side-lunge position with one leg bent parallel to the floor and the other leg straight to the side. Jump up explosively as you switch legs. Now the previously straight leg will be bent, and the previously bent leg will be straight to the other side. Try to keep your core tight and stay as low as possible as you switch sides as fast as you can.

Want more workout ideas? Try McCullough's ab exercises.