Abstract
Freely chosen cadence (CAD) represents a central rhythmic movement that has been suggested as resistant to internal and external stressors. Twenty participants cycled for 60 minutes at a constant Rate of Perceived Exertion (RPE) of 14 on an ergometer that permitted free manipulation of both CAD and resistance (TOR). During Session 1, inspired oxygen content (FiO2) was secretly manipulated in an A-B-A-B fashion between normoxia (21%) and hypoxia (16%) at 15-minute intervals. During Session 2, ambient temperature (Tam) was secretly manipulated between 20 and 35°C in an A-B-A pattern at 20-minute intervals. Subjects were deceived to the true nature of the study or the presence of any external manipulations. The synchronicity between power output (PO) and CAD and TOR was analyzed using Auto-Regressive Integrated Moving Averages. Changes in environmental conditions caused significant perturbations in PO that were highly correlated to TOR (FiO2 manipulation: stationary r2 = 0.962, Ljung-Box = 0.132 and Tam manipulation: stationary r2 = 0.978, Ljung-Box = 0.115), while CAD was unaffected (FiO2 manipulation: stationary r2 = 0.570, Ljung-Box = 0.258 and Tam manipulation: stationary r2 = 0.595, Ljung-Box = 0.289) during the manipulation of FiO2 and Tam, respectively. These findings support previous research that suggests that CAD is a centrally-regulated and voluntary motor behaviour that is unaffected by environmental stressors.
Supported by NSERC Discovery 227912-2007.
