Pull-ups are ideal exercises for strengthening back muscles. According to Men's Fitness, they are one of the best methods for sculpting a person's physique to sport a wider torso.
Men's Fitness differentiates between an underhand and an overhand grip, clarifying that the underhand grip is more correctly identified as a chin-up. It is a position that seems to prove more difficult for most men due to lack of flexibility, but it offers the best toning workout in terms of building up bicep and back muscles. Men's Fitness recommends doing a regimen of both pull-ups and chin-ups to achieve the best results.