Have five minutes to spare? Take your posture from poor to perfect with this quick back workout. Combining a variety of exercises from yoga to weights, this sequence will not only improve your posture, but it will help you with running, too. Beginners, try doing each exercise for 30 seconds and, when needed, rest in a 30-second Child's Pose. For an advanced version, complete each exercise for a minute, finishing with a long stretch.