PRAGUE (AP) — Two-time biathlon world champion Gabriela Koukalova has been ruled out of next month's Pyeongchang Olympics.

The Czech Biathlon Union says Koukalova won't recover in time from a calf problem that has kept her out of World Cup events so far this season.

Koukalova says "I tried my best to return" in time for the Olympics, but "unfortunately, I could not train as I had hoped. I'm very disappointed."

Koukalova is the reigning world championship and World Cup title holder in the sprint, and also has two Olympic silver medals.