When I met my wife she had a black lab and a golden/St. Bernard cross. She also had a 600 sqft condo. Those dog went on lots of walks and runs. You can do it, just gotta put in the time for them. We now have 3 acres and a dog door, much easier.
Mine's a field bred Lab, and she loves to run. I couldn't keep up with her even on a bicycle - she is FAST.
"Those dog went on lots of walks and runs. You can do it, just gotta put in the time for them."
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I'm sure there are exceptions, but the problem is just that they are exceptions.