She shared in the team gold medal at the 2010 IAAF World Cross Country Championships. She initially started out as a 1500 metres runner and came seventh in that event at the 2007 All-Africa Games. Muriuki placed sixth at the 2010 IAAF World Cross Country Championships, which helped the Kenyan women to the world team title.
She was the runner-up at the 2012 African Cross Country Championships behind team mate Joyce Chepkirui, both of whom shared the team title.
A week later she took third place at the Lisbon Half Marathon, finishing behind Diana Chepkemoi. She was runner-up at that year"s Portugal Half Marathon (also held in Lisbon).
Muriuki secured the Kenyan national title in cross country at the start of 2013, guaranteeing selection for the 2013 IAAF World Cross Country Championships.