Very difficult question to answer. It’s difficult for me to answer because of the different types of dogs there are (so many different breeds). Some dogs were bred for strength while others weren’t. It’s also difficult to figure out what the base is (the average dog). 

I can tell you what the basis for strength is - it depends on the cross sections of the muscles used to generate force and the intensity of the recruitment. That definition doesn’t make much sense because we don’t know what (intensity of the recruitment means). 

The average human is 42% lean muscle.