Never-Ending Tech Race

For nine years, Canadian triathlete Jasper Blake has been selecting from a menu of technological aids in a bid to get to the top of his eventa leg-sapping, lung-wringing combination of swimming, cycling and running that only the fittest, and perhaps dorkiest, athletes can win. "Triathlon is a nerdy sport," says the intense, lean, 1.7-m Blake. "We have the weirdest group of people into the most gimmicky, gizmo things."

When training on his bicycle, Blake uses the SRM Powermeter, a data-crunching disc attached to the bike's crank arm. Invented by a German company, the device measures the power...