I read the article where that 5 minute rule came from, the whole thing should be taken with a grain of salt. Most of the research that was used to make that recommendation was from human pediatric studies. Being a pediatric physical therapist as well as an orthopedic specialist I can confidently say the author misunderstood most of those articles and then applied them to something that isn’t human (which is understandable given that most people do the same thing with kids). A great example would be VO2 max not improving much with training in kids than adults. This is actually due to adults in the study being sedentary for years or even decades when compared to generally very active children who were already running around constantly before “training”. The author makes some good points and I do agree care needs to be take with certain activities (like jumping in and out of cars, stairs, and long distance running). I had a patient who is a die hard dog breeder and trainer share it with me and after reading I was shocked at how gospel it has become. There is likely a huge amount of variance if what a dog is safe to do depending on breed and genetics.