Haining won the British schools cross-country championship in 1985 when she was thirteen years old, and was seventh in the world cross country championships in Antwerp in 1991. After suffering some injuries, she gave up competitive running for four years after 1999. Haining competed in the marathon at the 2006 Commonwealth Games in Melbourne, where she finished ninth, and was the top ranked Scottish athlete in the race, despite suffering from flu beforehand. She failed to win the third team place in the marathon for the 2008 Olympic Games when she finished behind Liz Yelling at the 2008 Flora London Marathon. As of 29 July 2008 she was on standby to run in the marathon if Paula Radcliffe would be unable to do so. However, Radcliffe was fit enough to run, and completed the marathon in 23rd place.