EFFECTS OF THE ROTOR PEDALING SYSTEM ON PHYSIOLOGICAL INDICES OF ENDURANCE CYCLING PERFORMANCE

Abstract

PURPOSE To determine the effects of Rotor (ROT, a new cycle crank configuration that allows the pedals to move independently so that cranks are not fixed at 180°) on indices of endurance performance in trained cyclists compared with the conventional (CON) pedaling system. METHODS Ten cyclists (age (mean±SD): 22 ± 5 y) volunteered to participate in the study. On four separate days subjects performed four cycle-ergometer tests (two incremental tests and two 20-min constant-load tests). Both types of tests were performed with CON and ROT following a counter-balanced, cross-over design. An imposed crank rate of 75 rpm was used during all tests. The incremental test started at 112.5 W, and the power output was increased by 37.5 W every 3-min until volitional exhaustion. The power output for the constant-load tests with either system was set at a workload equivalent to 80% of the maximal power output (Wmax) achieved during the incremental tests using CON. Gas exchange parameters and blood lactate levels were measured in all the tests. RESULTS No differences (P > 0.05) were found between the ROT and CON systems for Wmax (337 ± 32 W and 331 ± 32 W, respectively), nor for the workload eliciting the lactate threshold (LT) (219 ± 26 W and 212 ± 26 W, respectively). No differences (P > 0.05) were found in lactate levels, economy or gross efficiency between the systems during the incremental or the constant-load tests. However, at exercise intensities between 60 and 90% VO2max during the incremental tests, DE tended to be higher using ROT (23.8 ± 3.3%) compared to CON (22.1 ± 3.6%), although statistical significance was not reached (P = 0.34; 95% CI = −2.2 to 5.7%). CONCLUSION Although more research is needed, commonly used indicators of endurance cycling performance, including Wmax, LT, and economy, were unaffected using ROT in trained cyclists.