Russian President Vladimir Putin said on Tuesday that teenage figure skater Kamila Valieva’s performances could not have been achieved with the help of any banned substances. Valieva, who turned 16 on Tuesday, failed a doping test at the Russian national championships last December but the result was only revealed on Feb. 8, a day after she had already helped the Russian Olympic Committee (ROC) win the team event at the Beijing Games. The case cast a shadow on Russians’ participation at the Games as they already faced increased scrutiny over separate doping sanctions that saw them compete with…