Chances are, you’re reading this at a desk or on your phone. Your shoulders are hunched forward, aren’t they? Your lower back is probably also curved opposite the way nature intended, and your glutes are asleep, possibly literally (depending on how long you’ve been frozen in place) — those muscles aren’t doing anything but sitting there.It’s not really your fault. A lot of what we do in life — from desk work to washing dishes to driving — uses more of the muscles on the front of the body, letting the back-body muscles weaken. The resulting muscular imbalances can lead to slumped posture, an out-of-whack lower back, underdeveloped glutes, and back and neck pain.Even our workouts often neglect those posterior chain muscles. For one thing, it's all too easy to spend most of our weight-room time facing the mirror and thinking about the muscles we can see: the biceps, quads, and abs.But beyond that, it's just not as easy to target what's going on in the back. “Most of the exercises you learn in gym class use the front-of-body pushing muscles because when you’re doing body-weight exercises, you’re using gravity as the resistance,” says Jessi Kneeland , a certified personal trainer and founder of ReModel Fitness. “It’s much easier to orient your body to push — rather than pull — against gravity.” That means in order to pull, you usually need a bar or some other equipment to pull against.Usually. Kneeland put together this awesome challenge for a strong back using no equipment at all (fine, you’ll need a bench or a couch for one move, but at least you’re not attaching anything to your doorframe). Kneeland suggests that eventually you’ll want to graduate to exercises with a bar, TRX, or dumbbells once these moves become too easy.