別府大分毎日マラソン
Yamanaka practiced judo (2nd Dan black belt) and played rugby as a university student. He also has a history of running marathons. After a 20-year gap, he competed in the inaugural Osaka Marathon in 2011 as a charity runner with a time of 4:29:53. He took part in Kyoto Marathon to raise money for iPS research since 2012. His personal best is 3:25:20 at 2018 Beppu-Ōita Marathon.