Running with Dogs

Question
I have a 6-month old Golden Retriever and a 4-year old Golden/Newfie mix.  I run with the 4 year old and it breaks my heart to hear the puppy cry when we leave without him.  How old should he be before I start the puppy running with us?

Answer
Hello..wel you can still take both dogs together for walks just don't run that puppy just yet see this website of rexercise nof of large bred puppies

http://www.newdogbreeding.com/keeping-your-large-breed-puppy-in-shape.html

I think running or strenuis exercsie for large bred puppies under the age of 6 or 8 months is what causes joint problems.