More and more people suffer from lumbar muscle strain due to lack of exercise. Cycling serves as both a stylish model of fitness and a training method in exercise and rehabilitation. A few of previous studies have examined the changes in lower extremity muscle activities during indoor cycling, but fewer data pertain to the low back muscles. This study aims to analyze the functional status of erector spinae during cycling by learning the regularity and characteristics of changes in sEMG frequency domain index-mean frequency (MF) within ten minutes. The statistical results showed that the values of 70% subjects fluctuated within the range of (0.04688±0.00125) Hz within the first 30 s and the values raised rapidly to the (150±10) Hz range after the 30 s. Moreover, the values trended to decline slowly in a fluctuating way after a while. However, no obvious regularity was observed among the remaining 30% of the subjects. Results of this study demonstrated that the muscle fatigue with a smaller level of low back began to emerge gradually after 30 s. Moreover, it is evident that cycling can be an incentive to the low back muscles in most people.