Abstract: Objective: To investigate the effects of low-intensity semi-squat KAATSU training on activation degree of core muscle groups and rating of perceived exertion. Methods: Ten young female wrestlers from Beijing team were recruited to perform 4 groups of half-squat exercises under the conditions of continuous and intermittent KAATSU and no KAATSU. The first group repeated30 times and the rest 15 times, with a load weight of 30% 1 RM. A special device was used to fix the KAATSU on the middle and upper third of the thigh, the pressure of binding KAATSU was set at 40 mmHg and the inflation KAATSU was 180 mmHg. Four tests were conducted before and after the KAATSU training program, the surface EMG signals of rectus abdominis, external oblique,erector spine and gluteus were collected, and the RMS standard values were calculated for each training. At the same time, after each group completed the training, rating of perceived exertion test was conducted. Results: 1) The RMSMVCvalue of obliqus externus abdominis was significantly increased after continuous KAATSU training and intermittent KAATSU training(P<0.05), and the RMSMVCvalue of erector spinae muscle was significantly decreased after continuous KAATSU training and intermittent KAATSU training(P<0.01). Time and group interaction had a significant effect on the RMSMVCvalue of gluteus maximus muscle(F=2.70, P<0.05). The RMSMVCvalue of gluteus maximus muscle was significantly decreased after continuous and intermittent KAATSU training(P<0.05); 2) Without KAATSU, the standard RMS value of rectus abdominis was significantly increased only in the last three squats(P<0.05); in continuous KAATSU, the standard RMS value of rectus abdominis was significantly increased before and after De-KAATSU(P<0.05); the standard RMS value of rectus abdominis after De-KAATSU of intermittent KAATSU training was significantly increased(P<0.05). The standard RMS value of obliqus externus abdominis was significantly increased with continuous KAATSU(P<0.05). The standard RMS value of erector spine was significantly increased after De-KAATSU in continuous KAATSU(P<0.05), but significantly increased before and after De-KAATSU in intermittent KAATSU(P<0.05); 3) In the four sections of Semi-squat training, the RMS standard values of rectus abdominis, external oblique abdominis and erector spinal muscles under KAATSU were significantly higher than those without KAATSU(P<0.05), but that was lower in gluteus(P<0.05).In the four sections, the RMS standard values of rectus abdominis, external oblique and erector spine muscles were increased group by group, while the RMS standard values of gluteus were decreased group by group. The interaction of time and each group had a significant effect on the RMS standard values of gluteus(F=3.81, P<0.05); 4) In the KAATSU state, the subjective fatigue of the 4 groups was significantly higher than that of the non-KAATSU state after the exercise(P<0.01), and the subjective fatigue of the 4 groups was significantly higher than that of the non-KAATSU state after the De-KAATSU(P<0.05). Conclusions: Lower extremity KAATSU semi-squat training can significantly improve the activation degree of rectus abdominis and external oblique muscles, and it also have training effects on gluteus and erector spine muscles, The subjective fatigue of KAATSU training was more intense than that of non-KAATSU training. In the whole training effect, continuous KAATSU is better than intermittent KAATSU.