The aim of this dissertation was to establish the force/pressure distribution under three different types of harnesses for guide dogs and to achieve the basis for further studies.
All harnesses were made of leather. In the first harness the mobility of the frame was restricted by loops. The second harness was padded in the spine-area. The third harness had a rigid connection with the frame.
The measurements were carried out in eight guide dogs, which led a trainer for guide dogs through a course, which should simulate the stresses of daily life. All dogs were clinically sound and showed no sign of lameness (ground reaction forces). The pressure exerted form the harness to the dog was determined by sensor strips (T&T medilogic Medizintechnik GmbH, sample rate 60 Hz, 0.1-4 N/cm²) and individually adapted to each guide dog. The time course of the pressure was cut in motion cycles via a marker on the left forelimb of the guide dog using a kinematic measurement system (Motion Analysis Corp., USA CA Santa Rosa, sample rate 80 Hz).
Each dog had to walk a course including following exercises: straight line, curve left, curve right, upstairs, and downstairs. Straight line was chosen as reference exercise. All harnesses and exercises were compared to each other.
At the guide dog ten regions were determined: "chest strap front right", "chest strap shoulder right", "chest strap front left", "chest strap shoulder left", "sternum right", "sternum left", "chest right side", "chest left side", "back right" and "back left".
In all harnesses the highest forces and pressures were found on "sternum right". In the reference exercise the first harness showed pressure values (2.03 ± 0.6 N/cm²) comparable to those of horse saddles with "serious deficiencies". In all other regions, the pressures are in the range of horse saddles with "excellent to good fit" (0 to 99.9 mmHg (0-1.32 N/cm²)..
It is noteworthy that the regions "sternum right" and "sternum left" are almost constantly loaded.
Contrary to previous assumptions the back regions are little affected, because of the lifting of the frame.