Ennis sets her sights on the Olympics

Sheffield's Jess Ennis begins the defence of her World Indoor pentathlon title in Istanbul tomorrow.

The London Olympics will be her main focus this year, but Ennis sees the World Indoor Championships as an important stepping stone.

She'll be up against Russia's Tatyana Chernova, who beat her to the world outdoor heptathlon crown in South Korea last year. Whoever wins could break the world indoor record.