What age can you start running with a dog?

Just like you..he needs to work into it..sounds like you have done the walks and shorts jog which is perfect. The real issue with longer jogs with a dog such as a Golden is joint health. In order to prevent over taxing the hips and knees while they are growing which can contribute later to hip dysplacia and other joint issues, a large breed dog should avoid long runs and jumping up or down from cars/sofas until they are at least one year old in age, 18 months is better for full growth plate closure.