MOSCOW — The head of Russia's race walking center has been banned for four years following an investigation into claims of systematic doping.

Russia is the dominant power in race walking and has won six Olympic medals at the last two games.

However, its reputation has been tarnished by at least 17 doping bans for athletes from the national elite race walking center in Saransk.

Center director Viktor Kolesnikov was suspended in August during a Russian Anti-Doping Agency investigation into “multiple disqualifications of athletes.”

He has been banned for four years, the Russian Sports Ministry said in a website statement, without specifying the exact reason for Kolesnikov's ban.

MADRID — Rafael Nadal says he will return to playing at the start of the year.The 14-time Grand Slam champion hasn’t played since having his appendix removed this month, forcing him to miss the season-ending ATP finals.Nadal says “I will play in Abu Dhabi in January, and after that I will play my first official tournament in Doha.”