the 'technical' stuff:
"We have researched and road tested for the past 10 years and now we are very pleased to present you 2 types of power curved cranks. According to SGS Taiwan test report, power-curved crank can increase 25~30% torque output between angle 0° (upper dead point) and ~60°. It has overcome technical difficulties on raising power efficiency in the bicycle industry for two centuries. Power-curved cranks use the design of the golden spiral ratio, which create more pedaling efficiency than traditional cranks can provide, so that no matter bike lovers or normal riders can enjoy more fun of speed and comfortable riding. Also, its bright appearance and improved manufacturing process enhance the value and outstanding of the bicycle. For the purpose of meeting the commercialization, the power-curved cranks can be installed on any kind of bike without changing manufacturing process. Also, the power-curved cranks provide wider range of gear ratios for bicycle designing. In addition to those advantages, using power-curved cranks can increase 30% rotational momentum."
and the results of 'research' here:
Where would you want to swim ?