Abstract: An arm structure comprises a first arm and a second arm. The first arm is attached to a base and extends generally upwardly therefrom, while being pivotable about an axis perpendicular to its elongated axis. The second arm extends horizontally outwardly from the first arm. A height of a distal end of the second arm above the base is adjustable. The arm structure is configured such that when the second arm is struck by a swinging golf club, the second arm automatically returns generally to the position relative to the base which it had immediately prior to being struck.In one embodiment, a resilient sleeve extends outwardly from a distal end of the second leg. In another embodiment, opposing first and second sleeves are provided at a juncture of the first and second legs. The second sleeve has an elliptically shaped surface adjacent an elliptically shaped surface of the first sleeve.