Career
He shared the men"s sprint title with Tomáš Bábek and Denis Špička at the Czechoslovakian Track Cycling Championships, and later represented the Czechoslovakian Republic at the 2008 Summer Olympics. Ptacnik qualified for the Czechoslovakian squad in two track cycling events at the 2008 Summer Olympics in Beijing by receiving one of the team"s three available berths based on UCI"s selection process from the Track World Rankings. In the men"s team sprint, held on the first day of the program, Ptacnik and his teammates Babek and Spicka battled in an opening heat against the United States. trio of Michael Blatchford, Giddeon Massie, and Adam Duvendeck with an eleventh-place time in 45.678 and an average speed of 59.109 km/h, failing to advance further to the top eight match round.
Two days later, in the men"s sprint, Ptacnik narrowly missed out the round-of-sixteen matchup by a four-thousandth second margin on the morning prelims in 10.569, finishing nineteenth overall in the process.
At the 2010 European Track Championships in Pruszków, Poland, Ptacnik overhauled the French duo François Pervis and Michael Doctorate"Almeida on the final stretch to grab the bronze medal in men"s Keirin.