As long as that you think? They are running with this guy, I know he thinks he is fast but to a dog, won't be that quick and he is only running 1.5 miles. I reckon 6 months should be fine to go out a 1.5 mile jog, no problem. If it's too much you simply stop or just take him out the odd day. I'd be surprised though if the dog actually runs all that way without wanting to stop and sniff everything in sight. That was why I was asking if they were on a lead.
i have no issue with taking a dogs for a long walk, i walk my dogs from 1 - 4 hours at a time. they are 8 months and 1 year, but I'