Mezue ahịrịokwu na-esonụ: Na 2012 U.S. Olympic Trials na Omaha, Nebraska, US qualifying zutere maka 2012 Olympics, Gemmell mere US Olympic otu maka oge mbụ site na-emecha mbụ na 1,500 mita freestyle na oge nke 14:52.19. Na 2012 Summer Olympics na London, ọ nọ n'ọnọdụ nke itoolu na prelims nke
1,500-mita freestyle na oge nke 14:59.05, ma agafeghị n'etiti mmadụ asatọ kacha elu na njedebe nke ihe omume ahụ.