Performance, Perceived Safety, and Comfort of the Alternating Tread Stair

This study determined the perceived safety and comfort of an alternating tread stair and a conventional ships ladder. The alternating tread stair and the conventional ships ladder were also compared with respect to travel time and missteps. Subjects in military uniform ascended and descended both the alternating tread stair and the conventional ships ladder under load and no-load conditions. In the load condition subjects performed trials while carrying a 9-kg tool box, and in the no-load condition trials were performed without the tool box. Results indicate that the alternating tread stair is perceived to be safer and more comfortable to use. Moreover, the alternating tread stair had significantly fewer missteps.