I was a athlete who ran about 2-3 miles a nite for about 25 years, before I was injured. I use to take the pups....however, 1 of my two always wanted to stop and smell. So I found myself doing more pit stops than I truly wanted. So I separated the walker and the runner, for different times.
The main medical issues I have found that affect our pups are the same that affect us, heat exhaustion, dehydration, injury, etc.
And like us humans, always check with your vet to make sure your pup is physically capable of participating in such exercise before starting.
Best wishes....