At Beijing in 2008, Brazilian pole vaulter Fabiana Murer would have been a good bet to challenge if not upset Russian world-record holder Elena Isinbayeva — that is, if Beijing track-and-field officials hadn’t lost Murer’s pole. After searching frantically for it, Murer was forced to use a pole that was the wrong size and ended up out of medal contention. After that frustration, the pole vaulter, now 21, fought her way back to the top ranks and defeated Isinbayeva last summer at the world championships, making herself the one to beat in London.