We have a mini dachshund - they are predisposed to having back issues - when he was 6 or 7 he suffered a minor injury. Couldn't go up and down stairs so I built a ramp from our back deck to the ground (about 2 feet, 3 steps). He refused to use it. Now he's diabetic and blind (he's almost 11) and still won't use ramps. Although he is darn good at navigating the house.
edit: I should have added that was with both of us coaxing him with food, treats, etc. he would not go up nor down the ramp which was about 7 feet long.