A 2006 study of non-elite Boston Marathon participants tested runners for certain proteins that indicate heart damage or dysfunction (see Troponin) and gave them echocardiogram scans, before and after the marathon. The study revealed that, in that sample of 60 people, runners who had averaged less than of weekly training in the 4 months before the race were most likely to show some heart damage or dysfunction, while runners who had done more than of weekly training showed few or no heart problems.