A shirt for improving a swinging motion of a user wearing the shirt includes front and rear panels each having corresponding top, bottom and generally opposing side edges, wherein the front and rear panels are adjoined to each other by the top and side edges, defining an interior space of the shirt. The front and rear panels include sleeve cutouts formed on each side edge adjacent the top edge, and a neck cutout formed on the top edges of the front and rear panels. At least one tubular sleeve is permanently joined to the front and rear panels of at least one of the sleeve cutouts, the tubular sleeve defining an inside area, the inside area being fluidly connected to the interior space of the shirt. A member is substantially adjacent to the sleeve cutout and the side edges of both the front and rear panels.