Katja Söhnel is a Scientific Researcher at Friedrich-Schiller Universität in Jena, Germany, Institute of Zoology and Evolutionary Research.
Her research field is in the dynamics of animals, especially dog locomotion. She used 3D kinetic and 3D kinematic data to investigate jumping dogs’ acyclic motions. She is interested in understanding locomotion and combining biology and mechanics/ robotics. Currently, she is working on an ontogenetic dog study to investigate how puppies develop into adult dogs.
Disciplines: Biomechanics, Biomedical Engineering, Zoology
Languages: German, English
Education
2012 – Bachelor of Science (Biomedical Engineering) – Technische Universität Ilmenau
2016 – Master of Science (Biomedical engineering) – Technische Universität Ilmenau
2021 – Dr. rer. nat (Zoology) – Friedrich-Schiller-Universität Jena
[Music] So hello Katya. Uh I am so happy that you could take time to join us here for this little talk and of course I am over excited uh that you will speak even have two speeches two lectures at our conference in September of 2025. Hello Petra. I’m also very excited and very happy um to have the talks on the conference. Yeah. So you are a scientific researcher at Yenna University and what is the current research you are um working on about? So uh yes I’m a researcher on the University of Vienna and um we are doing at the moment a very big project. It’s about um the development from puppy gate to adult gate of the dogs. So it’s a long-term study and um we try to measure the pups monthly and when they grow up and become older then we increase the time where we see them. So um we see them um every third or fourth month um when they are more than a year old. So we try to find out what changed from puppy gate to adult gate when it changed and if there’s something to change. But therefore we need a lot of puppies and it wasn’t possible to do it alone. So we had four locations in Germany which are also cooperating with us and we get a very big um database. So, we have more than 4,000 measurements um on the puppets. Yes, that’s a lot of data. And also, you have um at the university you have some amazing equipment. Uh do you are you using it in this study and can you tell me what makes it so unique? So, in this study we um we use an instrumented treadmill. So that’s the first um time we use instrumented treadmill. Um an instrumented treadmill means that uh we have a normal treadmill but under the treadmill bait uh belt there is um um matrix of um a lot of sensors and these are very tiny um pressure sensors. It’s more than 200 sensors are integrated um under the treadmill belt and therefore if dog is moving on the treadmill he didn’t get to know anything about the measurement so he’s still walking on the treadmill and we can sample with uh 200 um hearts and um we get informations about the roll offs of the PS and how they connected to the ground how they roll off and move on. Um we get informations from the forces um the pressure and we get some information from like um uh how long is the stride length or how um wide is the stride length um how long is the stance time, how long is the swing time and so on. And so we get a lot of informations from the instrumented treadmill. Um but before using this instrumented treadmill um we um made a research on how good is it and therefore we place the treadmill on different force plates and we put the dog on treadmill and let them trot and we measure uh with the we measure with the force plates what kind of force was um produced by the dog and we also measured with the treadmill and we compared um the force plates which is the gold standard um to measure forces um to the instrumented treadmill and we found that uh that there are uh only tiny differences and it’s a quite good instrument to measure the forces and we also take a look at um what’s the different between normal walking and treadmill walking regarding the forces and the stance time and we also found that there are only tiny differences and the differences are majorly caused cuz if I let the dog walk normal over the first plate. So, the dog is more looking to the left, to the right, he’s decelerating and accelerating and he’s not um at that constant speed. And we need a lot of um trials to capture um some good forces where the dog is only touching the force plate with one power and not with two and so on. Um and the instrumented thread model benefits from we need 30 seconds to capture more than 20 gate cycles. It’s not possible with force plates and the results are quite um um quite good as so we had a had a good comparability um between normal walking and treadmill walking. Um we know that there are some difference in the in the joint angles but um that’s not what we did compare. So we want to know what’s about forces and the pressure angle. Yeah. So the treadmill is um the major uh central part in our puppy study. Um but we have in Guina also different um yeah equipment and one of the special equipments is um the the X-ray. So it’s a biplanar um X-ray where we can have um movies from huge variety of animals. It should not only be dogs. It can be all uh all around the world. Um and we have um two cameras sampling with 2,000 frames per second. And um you can see um using the X-ray how the bones are moving when the animal is walking. And for everybody who’s interested in um you can use a internet browser search engine and type in X-ray movies ya and you will found the x-ray collection and you can have a look at different animals that were measured from I believe the first videos were recorded at 1993 up till today where some videos were made on um yeah a quite a variety of animals. So there are some snakes or some squirrels or a sloth is also moving um on a branch and um rats and so on and um of course also the dogs. So you can search there and take a look and um yeah you can see what we’ve done if you use the the online browser. Um, and also we use some kind of other uh stuff um like marker based um motion tracking. That’s um when you glue little tiny markers on the skin um of the dark and you have some high infrared cameras which would with a high resolution and um they send light flashing through the um um markers and the markers reflecting the light back to the camera and there you can see where the markers are moving um in the room. Um but then you measure what uh the skin is doing because you glued the markers on the skin. Um and we are normally interested on what the what the bones are doing and not what skin or muscle mass is doing. So um marker based motion tracking um it’s okay but um it has some problems even in dogs when we have a lot of skin mass and so on and the skin mass is moving and it’s moving the markers and that’s not that what we want to do. Um but we have also collaborations. For example, we have not that much cameras for motion tracking and we have not so many um force plates. And um in my research for my PhD, I did u um investigate what’s about the forces when a dog is jumping and landing and therefore I need a big lab with force plates and so on. and I moved um to the University of Müster and they have one of the biggest labs with I believe 18 cameras or something like this. So we measured a big in in a big room and the dog can move freely and jumping and landing and so on. And we measure this in synchrony with um with the force plates and we get informations about how um what kind of forces are reacting to the dogs um when they um take off before the jump and um when they land. And that’s one um one of the uh one of the talks that I will have on conference. I just wanted I just wanted to say that this all sounds so interesting and that I am so I can’t wait that you start your presentation at the conference and you will present what you are doing now and what your PhD was um at the conference but in your opinion if you look at all that was done on movement in uh Yenna University or University of Vienna um what would be in your opinion the most surprising or maybe important findings of the study? So, Professor Fcher was um uh investigating in an locomotion of dogs um some years and he did one of the greatest and biggest um research on dog movement and um I believe one of the most important findings uh is the connection between form and function and uh for example it’s uh becomes for me evident that unfortunately um many anatomical um dog scallets you will find at different universities or in the internet um that are assembled incorrectly because um you will often see that the hip joint is located at the level of the shoulder joint but that’s not true. So the hip joint should be located um at the level of the upper third of uh the scapula and um if you know this and you go with open eyes through the world then you can see a lot of wrong assembled skeletons um this makes a problem um because people believe that’s the way how a dog is standing or moving but this makes no sense um because the scapula functions um yeah almost like like like an additional limp segment. So scapula um contributes a lot to the stride length and this was long time um underestimated I believe and um how the scapula move is this rotationally and um and there’s a translation around um the rib cage and these are some things um that yeah that were not known before but were found out using the biplaner X-ray where we can see how uh how the bones are moving and we would not see this um in using um marker based motion uh tracking um when we glue something on the skin because there’s so much skin mass wobbling and so on where we could not find this and I believe this is one of the greatest um things um that were found out in the past um in the past dog studies um under professor Fusha and And we also see that there exist a parallelism uh in the liymph segments. So you will always see that the first and um third segments um where um for the form it’s the scapula and the antipraium um they uh maintain con consistently parallel orientation throughout the stance phase. So they are moving always in in parallel and professor FA call it the pantocraft but today nobody knows what a pantoraph is. So maybe we have to find a new word of this. Um but this parallel orientation of the first and third segment of the of the limb is also seen on the on the hind limb. So um how the scapular moves is uh yeah equal to um how the femur is moving and the femur and the u metatarsus are always in parallel position um during the stance phase and um that’s one principle um yeah one principle of locomotion that we see in all dogs right the huge uh variability and differences in in breeds Um if we take a look at at uh French bulldogs for example and and a greyhound um they are quite different but they are lo using um both the same um yeah parallelism and orientation in the first and third segments um of the of the limb segments. Yeah. And I believe that’s that’s one of the these are the the biggest uh yeah interesting results from the past studies but there are much more and it’s quite better to to tell or to talk about uh that if we can show it on on pictures and videos and so on. So maybe it’s Yeah. when I’m only talking about that. Yeah. And what was also interesting for me was that from the side, if you’re looking um at dogs moving from the side of different breeds, it’s basically all the same. Yeah. But that the huge difference is when you look at them from front to back or back to front, especially from like side hounds and shepherds and then to the breeds that are bred to be to have short nose. So like uh bulldogs and pugs and those kind of cuz that was for me that was kind of yes new information but also kind of scary and sad how they are moving because it’s always the problem and if we um if we change one thing for example if we want to have a shorter nose we are not only producing dogs with shorter nose um It have influence on the whole body of the dog. And uh yeah and if we go out from the from the lateral view um how all dogs move in the same way and we switch um to another view then we can see that um in making a short nose we um change how um yeah how the limb moves, how the rib c cage is is um change in length and therefore we can see how especially the knees are um moved on on out of the line. I I want to say out of the line maybe. Yeah. Um there’s a lot of um talk in the dog training world about um how much and how dogs should move or need to move. So in let’s say in your educated opinion or guess what would you say if we are looking at a healthy like average size dog let’s say shepherd um so without any anomalies how much would you say they need to move to stay healthy and vibrant? Yeah. So, um it’s at first it depends. It depends on on on a lot of factors. Um but um it’s important that the dogs can move and they had to move freely um not only restricted um on a leash or something like this. They have to move uh to run. they have to uh stop and run and change direction and so on and um they need different kind of movement. So it’s even it’s it’s not a good idea to only go on a walk or the dog is always on a bicycle and you are always um driving a straight way a straight path or something on. So the dog has to move freely. he needs different undergrounds and so on. And um only if he moves he can um grow up with muscles. So uh a dog lying on the couch would not produce any kind of muscle. Um that’s something we got often asked. Um how much movement needs a puppy? Yeah, just some some some rules. If let let me say the dog is 2 months old then you cannot um walk the dog longer than two 10 minutes or something like this. So that’s stupid. Such rules are quite stupid. So because it depends on the puppy and it’s even the same with a net dog and even um if he’s healthy. You always have to take a look is if the dog is tired or not. So if the dog is tired then uh make a break and then move on and on the next day you will know okay maybe that was a bit too much. So and uh I believe that’s uh that’s in pretty simple and easy way that we can go and not thinking on numbers. So, I can tell you 1 hour, but it uh it depends. Maybe for a dog that was only moved 10 minutes before and now I say for an hour and he goes out for an hour, it’s um pretty um hard for the dog. So, because uh yeah, the dog has to crew up with the activity level. So, go out, take a look, if it’s too much, make a break, then um start on the next day again, maybe a shorter round and so on. So yeah, let the dog move freely and if you see he’s tired, he can rest. Yeah, that’s what I would like to say. That’s a very good point that you just made that instead of trying to teach people how much dogs should move at what age or at what condition or whatever, we should more be focused on teaching people to recognize the signs of when the dog is tired. So, how does the puppy show that this was too much for him? How does the older dog show that he’s tired and he needs to just maybe maybe even just rest for five minutes before he continues. So just putting more emphasis on um teaching people to read the dogs than teaching them how long the walk should be. But also the other thing I liked that you said is that um not just the um amount of exercise but also what kind of exercise. So running next to the bike for I don’t know 10 15 kilometers can be as damaging as not walking the dog. Yeah. So, it’s a it’s a it’s a problem in not walking the dog cuz uh the dog needs muscle mass and uh if you not walk the dog uh he did not have uh an adequate muscle mass and um even if the dog has some joint problems um you had to keep him um active in uh what I mean is walk the dog. So um we have a lot of dogs with hip dysplasia. Yeah, hip dysplasia is always a big problem. Um but even if the dog gets some diagnosis, it’s I believe it’s not a good idea idea to take them out from any kind of sport and let them only lie on the couch. So that’s that does not help the dog. If uh the dog is active and uh then he has the chance that the muscles can compensate uh for some non-healthy um problems. So like like hip dysplasia and so on. I do not mean um make some high level sports or something like this. Yeah. Um but be active. find a find an adequate level where you can move the dog and what um yeah what you can do with the dog and there we are again on on the point that how’s the feeling of your dog or how is the dog comfortable um with the movement or not and um I believe some years ago we had a better feeling from our insight how the dog is today it’s only like we need numbers we need numbers and I take a look at the watch, but we don’t look at the dogs. So, I believe that’s a that’s a quite a problem. Yeah. And um and yes, I I believe um not moving can can cause um problems. Yeah. And um and it’s the same on the other side with extremely long movements or extremely strenous movements. For example, like uh bicycle, the dog next to the bicycle for maybe 15 20 kilometers. If the dog is get trained to this level, this could be okay. But do also some other things. Yeah. Um the problem is always if we do not um yeah do not have a full view on the dog. So we always have to find um different movements, not only go bicycle, not only go on on on hot surfers. Yeah. Not only do always one thing. So um there should be a variety of uh undergrounds movements, different things and so on. Yeah. And not only throw a ball. That’s quite stupid. You can also move too. Yeah. So that’s that’s something um is throwing a ball is Yeah. I don’t like it. I am pretty sure I’m pretty sure that at the conference there will be a whole debate about this and you said it so nicely. It’s years ago. So, previous generations had much more feeling for the dog. And now everything has to be written down, has to be numbers, has to be in, I don’t know, graphs and all of that. Otherwise, it’s not important. And we should start turning a little bit more towards having a little bit more feeling again. Yeah. Yeah. I believe that’s uh that’s one of the biggest points. So, I I get my first puppy 15 years ago and uh and today I get questions on how many minutes could I walk the puppy and it was like what I never thought about that on my own puppy because it was like oh okay that was a bit too much and uh now next day we take more time or um make the walk a bit shorter or something like this and today is only no this was one minute too much or something like this. So, so thank you. Thank you very much for joining me for this talk and I I’m again excited to see you at the conference. I’m excited too.