Influence of Two Types of Guide Harnesses on Ground Reaction Forces and Step Length of Guide Dogs for the Blind.

Abstract

Simple SummaryGuide dogs for the blind are an important tool for their handlers to live an independent life. As previous studies have shown, the harness has a significant impact on the dog’s kinematics and exerts pressure on special areas of the dog’s body. The aim of the study was to evaluate the influence of two types of harness on the force distribution between the paws. To measure the influence of the harnesses, we compared the vertical ground reaction forces in the working harness of a guide dog (Norwegian type) and in a Y-harness, each with a leash, a straight handle and a handle bent on the left side. Furthermore, the ground reaction forces were measured in dogs with collar and leash. Twelve certified guide dogs were included in the study. Compared to walking with collar and leash, none of the harnesses, when used with a leash, had an effect on the evaluated parameters. When the dogs walked in the harness with a handle and, as is common when leading blind people, under a light pull, there were clear effects on the impulse. Future studies should be devoted to the type of attachment of the harness, as well as the angle of attachment, which is altered by the size of the handler. Few studies exist addressing the effects of guide dog harnesses on dogs biomechanics. The aim of this study was to investigate how two different harness types affect ground reaction forces and stride length. Twelve certified guide dogs were tested under different conditions: walking with a collar and leash, walking with the harness used daily (Norwegian type with straight handle) and walking with a Y-harness using a straight or a curved handle. The parameters studied included maximum vertical force, vertical impulse and stride length. Compared to walking with a collar and leash, none of the harnesses, when used with a leash, had an effect on the evaluated parameters. However, both harnesses, when used with a handle and under re-enactment of the lead work, showed clear effects on the impulse. Stride length was shortened if the Y-harness with handles was used. Future studies should focus on the type of attachment of the harness, as well as the angle of attachment, which is altered by the size of the handler. The development of individually adapted harnesses in order to subject these animals to as little stress as possible during their daily work should be one of the future areas of research.