The dance workout known as Zumba may NOT be what gets peopleup and moving in the new year.

In fact, it's fallen off the American College of SportsMedicine's fitness trend survey.

Rebecca Williams is pushing a 160–pound sled across the roomas fast as she can...six times in a row.

Williams, who exercises regularly, says,  "Feels like you're pushing a car."

She and her classmates at Volt Fitness in New Jersey get ashort break after they push...but still...

IngridCastro, who exercises regularly, says, "I'll be feeling this all day!"

This is a type of high intensity interval training...shortbursts of activity...doing almost anything...followed by a short rest.

And for the first time ever, high intensity intervaltraining tops the list of  the AmericanCollege of Sports Medicine's fitness trends for 2014.

Neal Pire is a personal trainer who designed the workout toburn more calories than you eat.

Neal Pire with Volt Fitness says, "If you can pack in as many calories burned during atraining session as you can, the total calories burned are going to equalcalorie deficit."

And that's what leads to weight loss.

Pire's class also incorporates training using your own bodyweight – the second top trend for 2014...

He says all the back and forth, up and down, with minimalequipment makes exercise simple.

Pire says, "Simplicity really makes it easy for people to getstarted."

Williams was looking for a no frills workout.

Williams says, "I see results and it's worth it."

In her first 4 months, she lost 30 pounds.