Abstract: An apparatus for training a runner a proper arm-swing technique includes a body harness, and first and second engagement members for engaging the wrists or hands of the user. In one embodiment, the engagement members are grips that the user grasps while running. The apparatus further includes first and second upper straps configured to attach to the body harness and to the wrist coverings. The apparatus also includes first and second lower straps configured to attach to the body harness and to the wrist coverings. The body harness may be configured as a vest or formed from a plurality of straps. The arm-swing apparatus may further include first and second back springs configured to attach to the body harness and to a belt configured to fit around the waist of the runner. A method of using the arm-swing training apparatus is also disclosed.