As is said at the end of the article, this was largely beyond the control of us -- the States experienced a good deal of growth, with a tightening of their trade gap by 14% compared with our current account losing 2.7%. It does not help that the States has experienced a decrease in demands for unemployment payments (meaning more people on it likely found work), amongst other signs of economic recovery.
Given our general size and the strength of our trading relationship, especially our levels of trade between our countries, it would be of little surprise of the States was the driving force behind our decline by the actions of their nation sort of dragging Canada in the direction it went.
You can check out the related article from Bloomberg on America's growth
here. While bad news for Canada, it is good news for the States, since this has provided some moderately encouraging information towards reducing fears of a second recession. I'm sure the fact that the American dollar has been progressively getting weaker will help, while the Canadian economy, which had a low dollar for so long against the US, is having trouble with exports due to the increased price which comes from that increased dollar. All in all, the forecasts did call for the Canadian economy not to do wonderfully during this period, although having this come about was a good deal worse (by about three times) than what had been expected.
This story also got a mention on another recent Bloomberg story, in which Geithner (the US Treasure Secretary) mentioned the need for China to let the yuan float more. Another thread here was just started with discusses that aspect in more detail.
Hope I kept this short and to the point.