PURPOSE This study aimed to compare body composition, physical fitness, maximum muscle strength, and blood lactate concentration according to the level of aerobic capacity in Keirin cyclists.METHODS Forty-four Keirin cyclists participated in this study and were divided into three groups: the top 20% VO<sub>2</sub>max group (TG, n=9), the middle 20% VO<sub>2</sub>max group (MG, n=9), and the low 20% VO<sub>2</sub>max group (LG, n=9). The study measured body composition, physical fitness, maximum muscle strength, and blood lactate concentration in Keirin cyclists. Differences between groups were determined using one-way ANOVA analysis.RESULTS Body weight, percentage of body fat, and body mass index were significantly higher in the LG than in the TG and MG. The vertical jump and maximum muscle strength were significantly higher in the TG and MG than in the LG. Additionally, blood lactate concentrations immediately after exhaustive exercise and during the 5-minute recovery periods were higher in the LG than in the TG and MG. Moreover, the time to exhaustion, HRmax and maximum power were the highest in the TG.CONCLUSIONS Our findings suggest new information that levels of aerobic capacity in male Keirin cyclists might be a crucial predictor of cycling performance and recovery ability.