Featured in the Sept/Oct 2007 Issue of Mushing Magazine:Analogies between Mushing and other sporting endeavors are interesting and entertaining to make. One sport in particular, cycling, made huge leaps in performance when available technology was used for monitoring physiological systems and power output. For almost a decade, Don Cadwell has been gathering data on sled dogs’ performance. His latest evolution, is due out next year. It may very well prove to be the tool that can take sled dog performance to the next level.G.S. Tell me about your latest project, the K-9 Coach.D.C. Well when I first started Sled Dog Systems, it was meant to be a company that builds equipment that could measure dogs’ athletic abilities and performance. The reason for that is, before dogs, I was heavily into bicycling. That sport took a huge leap forward when we got serious about measuring outputs such as V02 max, blood oxygen levels, heart rate, etc. Looking at canine athletes, there is nothing really like that out there. There are some equine heart rate monitors by Polar, but nothing specifically for dogs. Sled Dog Systems became well known for the sleds that I developed, but I recently sold the sled manufacturing part of the business, along with the name, so I would have the time to get back to physio-metrics again. The goal is to be able to give trainers objective feedback on their dogs to enable them to evaluate their training methods. G.S. In cycling, I’ve noticed that heart rate monitors are being used in conjunction with power meters, to help cyclists tailor their workouts. Is that similar to what your tug line monitor can do?D.C. Yes, when you have heart rate and power output measured, you can plot the two and correlate conditioning and exertion level. Not perceived exertion, but factual data. When human athletes are training, at least they can subjectively communicate what their perceived exertion level is, it is much harder to do with dogs.G.S. What are some of the most important variables your system will be able to monitor?D.C. The three factors we will start out being able to monitor will be: Tugline tension, which combined with speed, will determine exertion level or work load. Respiration rate, which is an indication of heart rate. And the last one is body temperature.G.S. So you won’t be monitoring heart rate directly?D.C. No, in fact we’ve tried measuring heart rate for a decade. We actually have some systems that work quite well. The problem lies in developing a tool for the consumer to use. In horses and humans it is a lot easier for many reasons. One is that they both sweat, so conductivity needed to pick up the heart rate signal is more easily obtained. Another reason is that a horse’s heart rate is generally lower than a human’s so existing equipment can be modified to be used. Dogs, especially huskies, have a lot of fur and don’t sweat. Their heart rate can vary widely and beat much faster than a human heart. Applying a human heart rate monitor generally doesn’t work. We made several ekg monitoring systems built into a vest using electro-gel for conductivity, and a couple of those systems worked quite well. It gets tricky though. A dog has a lot of muscle in its chest surrounding the heart. When a dog is running it can be tough to differentiate the heart rate signal from the muscle contractions in the chest. We did come up with an ekg system using algorithms that worked pretty well. The problem is the vest has to be in just the right spot on the dog. You have to watch that the harness doesn’t move the vest around, and you have to keep the gel in there to maintain contact. For a laboratory type study it would be easy enough, but in practice, out in the field, with a team of dogs, it wasn’t consistent enough to sell to the public.G.S. How do you measure the respiratory rate of a dog, and how does that correlate to heart rate?D.C. The correlation of the two is what we are working on right now. We are doing studies in conjunction with a veterinarian’s office here. In a controlled environment, we’ll have dogs that we can monitor respiratory and heart rate data on simultaneously. We hope to work backwards and demonstrate that respiratory rate can be used as an indicator of exertion as heart rate is. To measure the respiratory rate, our current system actually listens to the air going through a dog’s wind pipe with a microphone mounted on the collar. G.S. Wow, that’s not as tweaky as measuring heart rate?D.C. Not really, one comparison I like to make is that, without aids, you can hear a dog breathe, you can’t hear a dog’s heart rate. The signal from the airway is actually quite large and easy to measure. You can put the measuring device on a collar and unlike heart rate measuring electrodes, placement and conductivity are not critical. One tricky thing with measuring air movement through a dog is when it is asleep or resting, the signal is very low compared to when it is working. There is a huge dynamic range of auditory signal that has to be compensated for.G.S. How much does the tug line monitoring device weigh? Does it affect the way a dog runs while using it?D.C. This new unit is actually the lightest one we’ve made. We like to place it between the tug line and the gangline, so the weight is not felt as much and the dog hardly notices it—if at all. The problem with placement at the gang line is that it is subject to being dragged on the ground when the line goes slack momentarily. We’ve had to make the housing out of very durable materials. The achilles heel of our older system was always the wires. This new system is completely wireless, and allows you to see real-time measurements. G.S. How does it work, and how accurate is it?D.C. There is a spring loaded cylinder inside, and a way to measure how far the springs compress. It is accurate to within 1 percent. It measures from 0-15 lbs. of work load.G.S. I remember Jeff King talking about how he used one of your earlier systems, and he was very surprised at how little weight a dog in his team actually is pulling. This led him to develop the harness that he uses, which gives the dog a bit more free range vs. the ability to pull real hard. D.C. That’s right, but Jeff is running large teams, and they are not sprinting. A 4-dog sprint team when working hard can pull 10 lbs. of weight, they can’t do this for long though.G.S. When you say, “Pulling 10 lbs. of weight,” what exactly does that mean? Is it equal to lifting 10 lbs. off the ground?D.C. We calibrate to a standard that is pounds-force. If you imagine a 10 lb. weight at the end of a rope, and the rope extended vertically, then turned 90 degrees around a pulley to a horizontal axis, 10 lbs. of force is the force needed to keep the weight suspended.G.S. How is the third variable, temperature, monitored while the dog is running?D.C. The collar has two temperature sensors. One we call an insulated skin temperature, where in close proximity on the throat, it measures the temperature of the dog. And the other is measuring the outside, ambient temperature. From that we’ve started to develop a correlation between those two readings and the core temperature of the dog. There is still more work to be done with the testing of this, but this way, there is no probe needed inside of the dog. It is an approximation, but we’ve found we can get pretty close.G.S. Ok, so now we’ve taken our team out, used the equipment, gathered the data, what do we do with it now? D.C. The way it is currently set up is to break the run into legs, so you can see the dog’s performance over certain parts of the run. The legs are completely adjustable, in fact during the run you can just push a button and start a new leg. It also keeps track of the time spent during each leg. If you know the distance over each leg, you can track speed that way.G.S. Why isn’t a GPS unit integrated?D.C. We do have one, but over short legs, if you lose signal at all, the error can be enough to affect your data. We do have a wireless transmitter for use on a bicycle or ATV, it works on wheeled training devices to allow you to get actual speed and distance data. Let’s say you have a 50 yard hill you want to get very accurate data from. You can set the leg to start at the bottom and end at the top, and even if you don’t know the distance, you can compare it to other runs over the same hill. You can get the time it takes to complete the leg, the average tension from the tug line, average and peak respiration rates, and body temperature during the leg. G.S. This is all really cool data to have, but just how useful is it going to be? Will it simply reinforce what most good mushers already know? They already know which is the best dog on the team because it pulls the hardest and doesn’t come back as tired. Do you see it teaching us things we didn’t know? How do you see the data specifically being able to help the average musher?D.C. To use the cycling correlation again, seat-of-the-pants training methods were used for decades, but once the first cyclists crossed the threshold and started to use real scientific methods in training, we reached a whole new level of performance. A lot of the things mushers use to evaluate dogs are subjective. Many things can sway your perception of a dog’s performance. I’ve found myself that dogs I tended to like more I ranked higher in performance in my mind. Once you are able to challenge your subjective judgement with an objective measurement, it can be a reality check for your training program. You’ll be able to test your objectivity. It opens up a whole new area for experimentation. For example, we found some of our dogs are more susceptible to high ambient temperatures, relatively speaking, than what we thought. Every variable can now be monitored and objective measurements can be obtained. You could run dogs in different positions, different times of day, change their diet, harness, booties, etc and see how it precisely affects their performance even if it only does in subtle ways. One thing that kept driving me to develop this is looking at race results. Most races, sprint or distance, are decided by just a couple of percent of total time. I don’t know of any musher who can look at a tug line and determine to within a few percent how hard that dog is pulling. Once that tug line is tight, it is very difficult to tell how hard they are really pulling. If you are training 20 dogs and you want to put together an 8-dog team you have to find a way to pick from that pool to get down to 8. If you can get objective measurements on performance you can eliminate a lot of the subjectivity that occurs as a result of preference or other reasons. G.S. What is the price range you are trying to hit with these units?D.C. A basic system with the receiver and tug monitor should be around the $400 range. Each additional module such as the collar should be around $200 additional. If the market is big enough the price should come down. When we started with our older system I actually had more interest from field dog trainers than from mushers. If this new system can appeal to many markets, the price will come down. G.S. Thanks for your time Don.D.C. No problem, Thank you.
