Photo by: Courtesy of Equinox Equinox- CITY: New York, Chicago, Los Angeles CLASS: ViPR What distinguishes this class is its primary tool, a large rubber cylinder (known as a ViPR) that is said to be the "evolution of free weights."
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By Ryan Halverson, DETAILS Health clubs and trainers are embracing the intense half-hour session. Here are the best group-fitness options.