We have a 7 month old working/show mix. We have taken him on many long forest walks where we walk and he sprints, jumps and bounds back and forth, covering about twice as much distance as we do. We took him to the beach a few times and he ran back and forth for a solid hour before showing signs of tiredness. Now we run with him (off leash) about 6 kms. Again, he covers about twice as much distance as we do, with the back and forth-ing, sprinting and stopping to sniff. We also have that nose-to-the-ground-not looking where he is going problem:)
All of this is off leash. Now I wonder if I missed the memo on not letting him run too much, but honestly, he is raring to go the next day, no signs of excessive exhaustion at the end of the day itself, and seems to really need the action. We space these activities out to about 1 per week on average. And we are pretty relaxed about it, stopping when needed, offering water, mixing in some recall.
I also run with him about 1 km each way to get him to the off leash park. This is purely for efficiency-sake on my part: giving him the chance to meet other dogs while keeping the whole excursion down to an hour. This is maybe every 3 days on average.
This is my first cocker puppy - indeed my first puppy - so curious to hear what others think on the subject too.