[bliss7373]

Each dog is different. Especially as dogs age, it's important to let them tell you what pace/amount of exercise is appropriate. Equally important - especially if you expect an older dog to endure strenuous exercise like running - is to get frequent check ups at the vet to make sure that hips, elbows, and heart are doing okay. These dogs are so stoic - they will often try their best to please us even when it hurts.

If there is a sudden or fairly rapid decrease in the dog's willingness to walk, I would certainly schedule a check-up with the vet. It can't hurt and could help you diagnose a problem early.