Reliability and Validity of Cycling Sprint Performance at Isolinear Mode Without Torque Factor: A Preliminary Study in Well-Trained Male Cyclists.

Purpose: This study aimed to compare the performance-derived parameters utilizing isolinear (ISO_LIN) and isovelocity (ISO_VEL) sprint cycling modes. Method: For that, 20 male trained cyclists performed 2 sprints of 7 s on an electromagnetically braked cycle ergometer in ISO_LIN and six sprints in ISO_VEL mode with cadences between 90 and 180 rpm, each separated by 3-min. A linear function modeled the sprints within each mode to extrapolate maximal cadence (C_MAX) and torque (T_MAX), and a quadratic function was used to extrapolate the apex defined as optimal cadence power (OPT_CAD) and peak power output (P_MAX). Fifteen subjects performed another 4 sprints at ISO_LIN mode on different days to verify the reliability. Results: The measures from the power-cadence relationship were not different between the ISO_LIN and ISO_VEL modes. Although significant differences were detected in the T-C relationship, T_MAX was greater at ISO_LIN than ISO_VEL (p = .006). On the other hand, C_MAX was higher at ISO_VEL than ISO_LIN (p < .001). The correlation between parameters was large to very large (r = 0.51 to 0.89). However, high limits of agreement were verified. The ISO_LIN presented consistency during the trials, and the random errors were acceptable (CV = 5.3% to 11.5%). Conclusion: Using the power-cadence relationship, P_MAX and OPT_CAD could be detected similarly between the two sprint modes (ISO_LIN and ISO_VEL). Thus, the findings demonstrated that a single ISO_LIN sprint test could be a suitable tool for quantifying the time course of muscle fatigue during and after cycling exercises in well-trained male cyclists.