Latest fitness fad: High-intensity interval training

There are several names for the routines, including P90X and Power 90 Extreme, but the drill is basically the same: intense spurts of exercise separated by lower-intensity periods of recovery. Workouts, like diets, come in fads. Taibo, mud runs, and Zumba, a form of dance workout, had their days. Now the trend is towards intensity intervals that co-opt cross-training such as martial arts, yoga and weight training. One benefit is that these workouts are short, usually lasting fewer than 30 minutes. According to the American College of Sports Medicine other fitness fads for 2014 include group personal training and yoga.