Everything is more fun with a friend, especially working out. Gisele, Jessica Alba, Miranda Lambert and Kim Kardashian are just a few stars who take advantage of the buddy system when it comes to fitness. Whether palling up for a hike in the Hollywood Hills, a yoga class or an afternoon of paddle boarding these celebrities are onto something. A new study presented in 2013 at the meeting of the American Public Health Association in Boston suggested that people enjoy physical activity more when they’re with others. So before you break a sweat, grab a friend!