Apparently the acronym ‘mamil’ was never coined as a description of middle aged cyclists - this term that has been adopted to describe men of a certain age riding bikes in a certain way has its roots in the sea, as a description of Australian men of a certain age in swimming suits.
Some bright spark is no doubt still glowing at the knowledge that he or she was responsible for introducing Mamil to everyday usage. Who knows, maybe they got a bonus for it.
Now, to rub salt into the wound, the term has made it onto Oxforddictionaries.com (not the Oxford English Dictionary, by the way, because that’s where real words live). But I guess a mention in an online dictionary from Oxford kind