Colombia's Fabian Puerta Zapata, the 2018 world keirin champion, was handed a four-year doping ban on Wednesday after testing positive for an anobolic steroid, the International Cycling Union (UCI) announced. The 29-year-old was sanctioned for the presence of boldenone, a substance banned due to its effect on the growth of muscle mass. The Colombian tested positive out of competition in June 2018 and was suspended in August the same year. He can appeal the decision at the Court of Arbitration for Sport (CAS). cfe/clv/dj/jc