Seminar Prof. Dr. Dr. h.c. Martin S. Fischer
Friedrich Schiller University Jena, Institute for Zoology and Evolutionary Research with Phyletic Museum, Ernst Haeckel House and Biology.
Wolves are enduring runners in a special way, be it to mark the huge territory or to run to big prey dead.
How many wolf is in the dog?
The domestication of the wolf has led to an amazing variety of dog breeds in size, weight, build and general appearance. The reasons for the greatest diversity among all domestic animals lie in the variability inherent in wolves and in the consequences of thousands of years old artificial selection. In the process, specific breeding was also carried out for changes in the musculoskeletal system.
With the world’s largest study on the movement of dogs to date, we have investigated the question of what effect the breeding choice had on the movement of the various dog breeds, especially considering, for example, that there is a fortyfold difference in weight between Chihuahua or dachshund and Great Dane.
Or do the dogs, regardless of their breed, move largely the same way? The focus of the first Jena studies on the locomotion of dogs was therefore the question of similarities and differences in the locomotion of different dog breeds. For this purpose, gait analyses of 327 dogs were carried out. It should be emphasised that in addition to the German Research Foundation (DFG), breed associations and the “Society for Cynological Research” (GKF), considerable financial contributions were made. The German Kennel Club (VDH) also supported the study and made the book “Dogs in Motion” (Fischer & Lilje 2011) possible.
Three different techniques were used to record locomotion: high-frequency videography, marker-based motion analysis (Qualisysâ) and high-frequency biplanar X-ray videography. We have been conducting the “Heel Study on Joint Dynamics” since 2014. For the first time, the three-dimensional motion sequences of the limbs in walking and trotting are measured with elaborate technology and the so-called inverse dynamics are calculated. The latter allows the performance in a joint to be recognized and the calculated work of muscles to be compared with electromyographic data. For the first time, the three-dimensional kinematics of five different dog breeds will also be investigated.
First results are presented and previously unrecognized movements in the knee or shoulder joint show how the body structure affects limb movement. In 2015 the book “Lameness investigation in dogs” by Daniel Koch and Martin S. Fischer was published. In the lecture, findings from this collaboration between the well-known Swiss veterinarian and a functional morphologist will be presented. fundamentals 1.)
Our study proves the extensive agreement in the locomotion of 32 dog breeds and even of Great Danes or dachshunds in the parasagittal leg guidance. This means that from the side all examined dogs show a largely identical movement pattern. The differences between ten dogs of the same breed are almost always greater than the mean values between the breeds. 2.)
Locomotion is not always generated by muscle work. Depending on the gait, energy is recovered in different ways from gravity-induced movement of the body’s centre of gravity. In order to be able to use such vertical movements of the body’s centre of gravity in a controlled manner, the legs must swing in unison, i.e. work with the same stride lengths and stride frequencies. This is only given in the symmetrical gaits (walk, pass and trot). The energy-saving mechanisms function most efficiently during cyclical locomotion. Manoeuvres such as acceleration, braking or even a change of direction and jumping are only possible with additional muscle work. 3.)
The mechanisms of the dog’s movement are therefore essentially aimed at minimising energy consumption and using gravity intelligently to save energy. Smooth, cyclical locomotion does not require complex control and great brain performance, but rather intelligent mechanics. This can compensate for disturbances caused by uneven terrain, for example. Technical literature has introduced the term “no-brainer” (Daley, 2008). 4.)
The “work” in locomotion is unevenly distributed between the front and hind limbs. When walking and trotting, even the braking forces predominate at the front. During the even, cyclical locomotion, the propulsion mainly comes from the hind limbs and here mainly from the hip joint. The pivot point of the front limbs is at the same height as the hip joint in the upper third of the shoulder blade. Around this moving pivot point, guided only by muscle power, the shoulder blade and thus the entire anterior ligament are moved.