Lower Limbs EMG Signal Analysis for Bottom Group of Muscles Fitness Norm Before and After Intensive Exercise

Physical fitness refers to the body's ability to adapt to work and environment, as well as the ability to function in physical behavior. This research is based on physical fitness, from the viewpoint of exercise physiology, muscle strength, muscle endurance, and muscle power, to quantitatively study physical fitness. In this study, standing long jump was used as a normal physical fitness test, and the lowest 20% group were screened from university freshmen. After intensive exercise training, the pre-and post-test results were analyzed under different intensities. A correlation between its time and frequency domain characteristics and muscle fitness was found, too. The subjects performed four different exercise intensities (No Load, 8RM, 18RM, 28RM) and plate experiments with weight-bearing squats. Their EMG signals during exercise were recorded for time and frequency domain analysis and analyzed by using the paired sample t-test to find the difference of the characteristic index of the lowest group under different exercise intensities. The research results show that after intensive training, RMS has significant differences in the 8RM exercise experiment, while MAV, VAR, and AAC do in the 18RM exercise experiment. Several time-domain indicators (RMS, AAC) and frequency domain indicators (MNF, MDF) have significant differences in the 18RM exercise experiment. MAV, VAR, RMS, and AAC have significant differences in the 28RM exercise experiment.