How often and how long can I run my dog for?

I have a lab that will be 2 in several months. She is 86 lbs and my vet told me she should loose about 6 lbs. Today for the second day in a row I took her out to a straight paved trail to run beside be as I longboard. She runs nonstop for 10 mins straight pulling me about 10% of the time. I then give her water and rest her for 30 minutes and go back the same distance non stop. Can this be hurting her if I do this 2-3 days in a row? Should I do this once every other day? Can I safely do this for a longer duration of time? I can only do this on Fri, Sat, Sun. Other than this the only exercise she gets is normal daily walks. P.S. she has a vest and loves pulling me, I have gotten to speeds of 20 mph with her pulling me on my board. So in no way shape or form am I abusing her and working her as a horse.