I figured I would make this a thread so I could find it easily.
My boy loves his treadmill. I started with a cheap, old electric treadmill that was in my grandmothers basement for years. There are carpet mills or slat mills specifically for dogs, but free was in my budget. I went really slow, if they spook they wont want to get back on so you do not want to spook them.
You MUST take your dog to the bathroom before you put them on the treadmill. you do not want them to go on the mill for their sake and your own.
You must NEVER leave your dog unattended while they are on the treadmill.
Attach a leash to the treadmill (I just tied mine around the bar). You want enough give so that the dog will not feel the resistance while on the treadmill but not too much that they can fall off the back if they lose their footing. The leash helps them stay on track.
I started asking my boy if he wanted to go on the treadmill and I would lead him over to the treadmill, onto the conveyor belt and reward him when he stood on the belt. I did this a few times until when I said "treadmill" he would go stand on the belt.
Then I added the word "ready" so he would know I was about to turn it on. the key is reward reward reward. Some dogs are not food motivated and are able to go off praise alone. Some dogs will work for their toys. My boy requires food. I use little bits of string cheese so he doesn't have to chew. I used to use bits of treats but stopped when he coughed one time and it made me nervous he would choke)
The key is to go super slow at first. This is day one with my boy, sorry for my creepy dog voice.
this is day 2
This is day 3, by this time he was trying to break the door down when i asked him if he wanted to go on the treadmill.
this was just another example
Start slow, watch your dog for signs they are done. Mel starts looking around and I can tell he is done. Usually I have to be the one to end it though, he would run all day if I let him. I have a new treadmill now, it has an incline and I set that to 4% incline and 4.5mph When we started it was 0% incline and maybe .5mph, I didn't have a gauge on my old treadmill. You know your dog and you know how they walk so they will help you decide what speed works. When Mel starts to slow down I remind him to get back to the front and try to make sure he stays centered which is why its VERY important to supervise 100% of the time.
Be aware, you may create a treadmill hog who doesn't understand why you are going on HIS treadmill and he isn't able to use it... Punk!