Kanstantsin Sivtsov (or Siutsou (; à Âacinka: Kanstancin ViktaraviàSià Âcoà Â; born 9 August 1982) is a Belarusian former professional road bicycle racer, who rode professionally between 2001 and 2018 for the Itera, Lokomotiv, , , , , , and squads. He retired after provisionally being suspended from the sport following an adverse analytical finding for erythropoietin (EPO).
Sivtsov was born in the Belarusian city of Gomel in 1982. He won the under-23 road race at the UCI Road World Championships. Sivtsov joined for the 2007 season, and rode the Tour de France, finishing 32nd overall.
Siutsou moved to for 2008, where he took his first stage race overall victory at the Tour de Georgia, and came 16th overall in the Tour de France. In the 2009 Giro d'Italia, Sivtsov won his first two Grand Tour stages, the team time trial on stage one and a successful solo breakaway in stage eight.
Sivtsov enjoyed his most successful year in 2011. He finished tenth overall in the Giro d'Italia â again winning the team time trial stage â with an eighth-place finish in the Critérium du Dauphiné, and won the Belarusian National Time Trial Championships for the first time.
Sivtsov moved to for the 2012 season. He was part of the teams that helped Richie Porte win the Volta ao Algarve, Bradley Wiggins win ParisâÂÂNice, the Tour de Romandie and Critérium du Dauphiné, and Michael Rogers win BayernâÂÂRundfahrt. Sivtsov was selected to ride the Tour de France as one of Wiggins' main domestiques, but crashed out on stage three with remaining with a fractured left tibia, the first retirement of the 2012 Tour.
Sivtsov claimed a solo win on stage two of the 2013 Giro del Trentino.
In October 2015, he announced that he would be leaving Team Sky after four seasons to join for 2016.
On 5 September 2018, the UCI announced that an out of competition test had resulted in an adverse analytical finding of Erythropoietin in a sample collected 31 July 2018. Siutsou was provisionally suspended pending the result of any B sample test. This followed his back injury sustained whilst carrying out a recon of the time trial at the Giro earlier that year.
On 23 June 2020, he was given a four-year ban for doping using EPO.