The SRM (Schoberer Rad Messtechnik, Welldorf, Germany) power monitoring System has been used extensively in applied field based studies to provide an accurate measu-rement of cycling power (Gardner et al. 2005). The SRM System consists of a PowerMeter (instrumented crank), a PowerControl (data logger and onboard data display), and a sensor cable (linking data transfer from crank to the onboard powercontrol). One limitation of the SRM System is an inability to attain power Outputs until one entire crank revolution is achieved. A crucial element of track cycling time trial events is the Standing Start in which the athlete is generating maximum torque at low cadence. In this performance setting the cyclist accelerates the bicycle from rest and consequently initial power data is not recorded by the Standard SRM system. A modification to the SRM system is described which allows for collection of instantaneous crank torque. The modification consists of an electronic de-modulator developed by SRM and a multi-channel datalogger (DL16CAN, Tellert, Germany) connected in series between the PowerMeter and the PowerControl. The pulse width modulated signal from the PowerMeter is de-modulated into a cadence voltage signal and a torque frequency signal. The signals are synchronised and recorded separately on a time base. The modification allows crank torque to be acquired at 200Hz. This equipment has opened up a new avenue of analysis in a previously under-researched and ultimately performance impacting area of track cycling.
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