Changes in cycling efficiency and performance after endurance exercise

Purpose: This study was designed to examine the effects of moderate-intensi ty endurance exercise on cycling performance, gross efficiency, and 30-s sp rint power output. Methods: Two separate experiments were conducted. After a controlled warm-up, subjects completed as much work as possible in a 5-mi n performance test (EXP1) or a maximal 30-s sprint test (EXP2). These initi al exercise bouts were followed by similar to 60 min of cycling at similar to 60% (V) over dot O-2peak or an equivalent period of rest (control) befor e repeating the warm-up exercise and either the 5-min performance or 30-s s print test. Expired gas for calculation of cycling gross efficiency was col lected over the last minute of each warm-up period. Results: Average 5-min performance pou er output was significantly reduced (12 W) after exercise i n EXP1, and in EXP2 both peak and mean power output were significantly lowe r (26 and 35 W, respectively). Gross efficiency decreased significantly wit h exercise in both EXP1 and EXP2. Moreover, the change in gross efficiency was correlated with the change in 5-min performance (r = 0.91, P < 0.01), b ut not with the change in mean or peak 30-s sprint power output. Conclusion s: After sustained moderate-intensity cycling significant reductions in 5-m in performance, gross efficiency and sprint power output were observed in e ndurance trained cyclists. The reduction in 5-min performance was related t o the exercise induced decrease in gross efficiency.