The SRM (Schoberer Rad Messtechnik, Welldorf, Germany) crankset was one of the first portable power measuring tools available to the cycling community as a large, albeit at a high price. The SRM system calculates power output from the torque and angular velocity generated at the bottom bracket of the bicycle (E. Farria et al, 2005). This is achieved through a system of strain gauges located between the cranks and the chainrings which measures the deformation between the two. This is proportional to the torque being generated during each pedal rotation. Several studies have validated the crankset and its test to test repeatability (A. Gardner et al., 2004; W. Bertucci et al., 2005; S. Duc et al., 2007;A Juekendrup et al, 2003) and it has been shown to be a valid system in both laboratory and field conditions. Variations of the crankset now exist for both scientific measurement (accuracy +/- 0.5%, weight 827g), Professional (accuracy +/- 2.5%, weight 560g), and amateur (accuracy +/- 5%, weight 640).
Thursday, August 12
Maybe of help to anyone thinking about a power system. Quick chunk nabbed from my Lit Review I'm working on:
Posted by Greg May at 18:18