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RESEARCH PRODUCT

Effect of cycling cadence on contractile and neural properties of knee extensors.

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LEPERS, R., G. Y. MILLET, and N. A. MAFFIULETTI. Effect of cycling cadence on contractile and neural properties of knee extensors. Med. Sci. Sports Exerc., Vol. 33, No. 11, 2001, pp. 1882–1888. Purpose: This study investigated the effect of prior prolonged cycling exercise performed at different cadences on subsequent neuromuscular characteristics. Methods: Eight well-trained triathletes sustained 80% of their maximal aerobic power during 30 min at three cadences: the freely chosen cadence (FCC), FCC20%, and FCC20%. Maximal isometric and concentric (120°·s 1 and 240°·s 1 ) torques were recorded before and after the exercise. Central activation, neural (M-wave), and contractile (isometric muscular twitch) parameters of quadriceps muscle were also analyzed by electrical stimulation of the femoral nerve. Results: Reductions in maximal isometric (P 0.01) and concentric torques at 120°·s 1 (P 0.05) were found after exercise. Central activation levels fell significantly ( P 0.05) by 13–16% depending on the pedaling rate. Although the M-wave did not significantly change after exercise, the ratio EMG RMS/M-wave amplitude decreased significantly (P 0.01) on both vastus lateralis and vastus medialis muscles for FCC20% and FCC but not for FCC20%. Significant decreases in maximal twitch tension (P 0.01), maximal rate of twitch development (P 0.01), and time to half relaxation (P 0.01) were observed postexercise with no effect of cadence. Conclusions: These findings suggest that force reduction after prolonged cycling is attributable to both central and peripheral factors but is not influenced by the pedaling rate in a range of FCC