The word "soccer" is an abbreviation of "Association Football" (aSOCiation football). This term was used in the UK to distinguish it from other forms of football, including "rugby football". Over time the sport of rugby football came to be known in the UK as "rugby", whilst for the sport of association football the term "football" came to be used more and more, usually at the expense of "soccer". In the US, the word "soccer" was preferred from the outset, perhaps because "football" was already used to describe that other popular American sport.

I have thought about this before and I have read on several websites that the word football has always implied a variety of games played on foot, not just those that involved kicking a ball. In the United States Soccer used to be called Association Football. It was not called soccer. Only after the Second World War was the sport commonly referred to as “soccer.” Perhaps due to the growing impact of the NFL (American Football),

The reason Americans use their hands so much is that their feet are already being used to do the running.