I was always told 20mins off lead is far better than pavement pounding until the pup is about a year old.
Then gradually build them up.

What you dont want is the pup to build muscle until they have finished growing around 18mths.

As much as the socialisation is good, the pup could be learning to rough play with the other dogs and when you have a 70kg dog at the end of the lead, this is dangerous.

With a Giant Breed the 5min rule works!

If they continue with this sort of exercise the poor pup will end up with terrible hips.

Try and be diplomatic with the owner and please explain this before its too late!

with phoebe (bullmastiff) we had 1 walk aday. it was 5 mins to the playing field then a good 30 -40 mins playing and mooching around then the 5 mins back. we did that from 10 weeks till about 6 months and then we added a 20 min road walk to get her better on her lead ect. by age 1 we were doing a 4 mile walk in morn but this was at plodding speed and took about an hour and a half and 40 mins free play in field at tea time. Shes 5 now and although she has many problems joints and muscle have never been one of them. I thinks its all about each dog, what they are fed, supplements and where your walking and what surface your walking on and the speed your doing so - ive seen people power walk with pups on the pavements i dont think that is good for them

You could always try the...

"my friend has a giant breed, but unfortunately its having real problems with its joints. It went to the vets who explained about the excercise limitations of these types of dogs. First i have heard, but now i have researched into it... how do you get on with your dogs." -- well along those lines.

To be honest, I wouldn't bother telling the owner what to do and what not to do. one and a half hours is nothing compared to some places where people place their dogs.

I used to work in a dog day care, and dogs of all ages were allowed to run free for 5 hours, with only a half hour break for lunch and a kip... which IMO is much worse.. owners have said how delighted they are that their dogs/pups sleep all night and give them no trouble at all... which i think is worrying as no pup should be so sleepy at night that it doesnt want to spend time with its owner.

The pup needs socialisation, play and sleep in short bursts each day... you could however suggest to this person that 3 half hour walks a day would be more beneficial to the pup than one long walk.

I would speak to the owner, some people don't realise the possible damage they are doing at this young age. They wrongly think that the dog will stop when it's tired.
The five minute rule is a good simple guideline however isn't entirely correct. What you have to remember is that a dogs skeleten grows in stages and areas have to knit etc, this can take up to 2 years. The type of excercise when they are young is also important. Excercise should be calm free running as opposed to run around like a maniac with other dogs, twisting and turning everywhere.

I think it partly depends on the breed of dog and type of exercise mine get plenty of supervised free running as pups but little road work until after 20 weeks, the min age to be able to complete AD- endurance test(12mile) is 14 month if the dog by that age hasnt got the stamina it cant complete it, also having good gluteal muscles help to stabilise the hip joint and prevents DJD, highest hip score I have had is 2:4 lowest 0:0.

hello there ,iv got large dog experience,and i feel that to much is all about the dog,when the dog has had enough they will show it .i do not force exercise at that age.they tell me.iv got a fenced yard and the dogs run free with in the fence. if its a controlled walk, i plan for a pooped dog not a dog that will not make it to the end, they should be forced to go untill there weak..having said that ,my pit pup is now 16 months and just starting to strengthen up and exercise is more for him at this time.iv got a 4 year old pit who does not rest, very hyper,and well exercised..runs allllllll day!

sorry ,they should not be forced,to go untill there weak,sorry..