Short-sleeve shirt, long-sleeve shirt, sports shirt, athletic shirt, and other articles of clothing. A shirt includes one or more regions that de-couple the movement of arm-regions of the shirt (or sleeves of the shirt), from movement of the chest-area or trunk-area of the shirt. A sports shirt includes: a right-side short or long sleeve; a left-side short or long sleeve; a front area to cover a chest of a wearer; a back area to cover a back of the wearer; an optional collar; a right-side decoupling region to decouple movement of the right-side sleeve from movement of the front area and the back area; and a left-side decoupling region to decouple movement of the left-side sleeve from movement of the front area and the back area.