While some trends are best left alone—harem pants, anyone?—this is one we can get behind: High-intensity interval training will be 2014's biggest workout trend, according to an American College of Sports Medicine (ACSM) survey of nearly 4,000 fitness pros.
This is the first time high-intensity interval training (HIIT) has appeared on the ACSM's annual list of fitness trends. Survey participants said the short bursts of high-intensity activity are both time efficient and a faster way to get fit. In fact, a recent study found that women who did 12 weeks of HIIT lost more belly fat and more weight overall compared to a group who did moderate exercise.
Body weight training, qualified personal trainers, strength training, and exercise for weight loss rounded out the survey's top five.
Exercises on their way out: Zumba, Pilates, indoor cycling, and stability balls all dropped off of the list in recent years. (This isn't to say they aren't any good, of course.) Yoga is actually making a comeback since dropping off in 2009.