I walk 30 minutes before i put him on the treadmill yes. But this was definitely way to much....
You know you done the wrong thing in the end, and still i did it.... i always have to learn the hard way one time.

i had put him on the mill with a harnass instead of a collar since thursday. i was watching back a video of today and it also looks like its pulling him up a bit. maybe he cannot correctly put his front legs on the ground?