tow or toe the line

Another instance of "...hmm, I did not know!". I was reading the latest blog of Bob Rae and came across this phrase, toe the line. At first I thought did he spell that correctly? So a quick google search and Voila!, the meaning below, was found on a blog about grammar.

"The phrase "toe the line" is equivalent to "toe the mark," both of which mean to conform to a rule or a standard. The Oxford Dictionary of Word Histories (Oxford: Oxford Univ. Press, 2002; ed. by Glynnis Chantrell) says, "The idiom toe the line from an athletics analogy originated in the early 19th century" (514).

The specific sport referred to is foot-racing, where the competitors must keep their feet behind a "line" or on a "mark" at the start of the race--as in "On your mark, get set, go!"

So one who "toes the line" is one who does not allow his foot to stray over the line. In other words, one who does not stray beyond a rigidly defined boundary."

Source: "http://grammartips.homestead.com/toetheline.html"