 Complete the following phrase:  Sanders career peaked in 2007 when she won the 400 metres at the 2007 European Indoor Championships breaking the British Indoor record, and ran a personal best to win the silver medal at the 2007 World Championships behind compatriot Christine Ohuruogu. In the 4×400 metres relay, she won a bronze medal at the 2008 Beijing Olympics retroactively awarded in 2017 and a gold medal at the 