This article was originally published on March 24, 2016.Ever hear your grandmother's sweet voice in your head, reminding you to stand up straight, dear? She was just trying to help, bless her heart. But in this day and age, achieving better posture can be easier said than done. “We have a major, major issue with people so obsessed with cell phones,” says Charleene O’Connor, a postural alignment and muscle biomechanics specialist and founder of Charleene’s Above and Beyond Fitness in New York City. “This, along with sitting all day, is making everyone’s posture worse.”And it’s not just the problem of rounded shoulders and chins jutting forward that you’d expect from staring at screens in every waking moment — posture affects your whole body. “When the whole top of the body is forward, the butt has to stick out, then the calves get tight, and you’re out of whack,” she says.So, how can you whip yourself back into shape?First, set up your workstation as ergonomically as possible. “My clients who have stand-up desks are happiest,” says O’Connor. If the boss won’t spring for new furniture, adjust your chair so you can sit up straight with your shoulders back and chest open, and center your computer screen (or screens) in front of your eyes. When reading your cell phone, hold it up rather than craning your neck down, and use an earpiece so you’re not crooking your head toward the handset (or if you’re trying to go hands-free, jamming the phone between your ear and your shoulder).Then, try this 30-day challenge, which will lengthen tight muscles and strengthen weak ones to have you standing taller, with less neck and low back pain. For best results, don’t rush and be a stickler for form — doing posture-correction exercises with bad posture kinda defeats the purpose.BTW, good posture doesn't mean forcefully squeezing your shoulder blades together and sitting like you have a metal rod attached to your spine. When the right muscles are working in the right way, good posture should feel upright, yes, but mostly just aligned and natural.Let's get started.