Hradilek competed in the 2008 Summer Olympics in Beijing. In the K1 event he finished seventh in the qualification round, thus progressing to the semifinals. In the semifinals he finished eleventh, failing to reach the final round. At the 2012 Summer Olympics in London he won a silver medal in the K1 event. He recorded a time of 94.78 seconds in the final which was only beaten by Daniele Molmenti (93.43 s). He also started in the C2 event with Stanislav Ježek where they finished ninth after being eliminated in the semifinals.