As of 2012, Zelinka's coach is Les Gramantik. During the 2012 Canadian Olympic trials for track and field, she set a new personal best, of 6599 points, and new Canadian record score for heptathletes, on 28 June 2012, besting her old personal best and Canadian record, set at the 2008 Olympics. This selected her for the 2012 London Olympics for heptathlon. Two days later, she finished first in the 100 m hurdles, qualifying her for that event as well. She had considered foregoing it to concentrate on the heptathlon, but decided to compete in both events. At the 2012 London Olympics, Zelinka finished 7th overall in both the Women's Heptathlon event and the 100 m hurdles.