A Bi-Kinetic Technique To Assess Fatigue: 2710 Board #230 June 2 9

Fatigue during maximal cycling is often quantified as relative change in torque (T) or power (P) as Fatigue Index (FI). FI however, does not account for changes in cadence (C) which impacts both P and FI. We investigated a method, Bi-Kinetic cycling, to quantify fatigue and account for changes in C. We then tested the validity of our results by using rested and fatigued T-C relationships to predict P throughout a Wingate test. PURPOSE: To evaluate fatigue using Bi-Kinetic cycling and develop a P model for short term maximal trials. METHODS: Four cyclists completed six 25s maximal Bi-Kinetic cycling trials. For the first 18s C was held constant at 90, 125, or 160 rpm. C was then changed to one of the other values for the final 7s. The 6 C combinations produced three T-C relationships representing fatigue states resulting from pedaling at 90, 125, and 160rpm. Linear regression of T-time data was used to estimate the T that would have been produced during the C transition period. Slopes of the fatigued T-C relationships were compared to the rested state. Rates of changes in maximum T and C with respect to time (dTmax/dt and dCmax/dt) were evaluated. dTmax/dt and dCmax/dt were used to model the T-C relationship as a function of time and C and thereby predict P during a Wingate test. Finally, those T-C relationships were used to determine optimized maximum P throughout the Wingate test. RESULTS: Slopes of the rested and fatigued T-C relationships differed (p < 0.05). dCmax/dt was significantly influenced by the fatiguing cadence (p < 0.05) but dTmax/dt was not. Modeled P was highly correlated with actual P during the Wingate test (p < 0.001, r2 = 0.96). Maximum optimized P was greater than actual P during most of the Wingate test. CONCLUSIONS: We used Bi-Kinetic cycling to quantify fatigue while accounting for C. Our results show that fatigue is influenced by C. Our model accurately predicted P during maximal fatiguing exercise. The constant load Wingate test results in less than optimal P.