FOCUSING ON YOUR IPHONEThe thought of going to the gym doesn't exactly thrill us either, which is exactly why we want the most efficient (read: shortest) workout possible. That means eliminating all distractions. So resist the urge to check your inbox every 30 seconds or text your friend to make plans. "If you're emailing or reading, you're not working out hard enough to lose weight," says Kacy Duke, a personal trainer at Equinox Fitness Clubs in New York City. We know—but you keep all your adre…