In gyms everywhere, high-intensity interval training replaced hour-plus cardio sessions. The prevalence of these short, full-body circuits is most evident in the popularity of CrossFit's intense, minutes-long "workouts of the day." "Shorter workouts allow greater intensity," says Ryan Halvorson, senior editor of 'IdeaFitness Journal.' "That's why marathoners can be gaunt or plump, while avid CrossFitters tend to be lean and muscular."
Credit: Getty Images
Powered By ZergNet
Sign up to receive the Men’s Journal newsletter and special offers from MJ and its marketing partners.
Gear of the Year
103 Must-Have Gadgets, Tools & Toys
Plus: The Plan to Save Africa's Rhinos
ON NEWSSTANDS NOW