I agree with both bckrazy & dragondawg.

I think it's wise to error on the side of caution and not overdo the exercise, especially with the weather heating up.

It's safer to "add on" mileage gradually then to have to fix an injury caused by over stress after the fact.

'Having injured my dogs cruiate ligament last year from too much....I know what I speak of--although every dog and situation is unique.