Abstract: ObjectiveTo explore the relationship between muscle fatigue and pain in lumbar muscle fatigue induced test. MethodsFrom July to October, 21 healthy female volunteers were subjected to the fatigue induced test. Their root mean square (RMS) and median frequency (MF) of the surface electromyography were collected, their fatigue were assessed with Borg Fatigue Scale and Visual Analogue Scale (VAS), and their maximal voluntary contraction (MVC) and pressure pain threshold (PPT) were measured, before, during and after experiment. They were divided into pain or no-pain groups according to the symptom, and the differences before and after test were compared. ResultsThere was significant difference in the scores of Borg Fatigue Scale and VAS, MVC, RMS, and MF after test (Z>6.064, P<0.001). There was significant difference between two groups in all the data before test, and there was significant difference between two groups in the difference before and after test of the VAS score (t=-4.112, P=0.001) and RMS (t>2.385, P<0.05) in some points. Receiver operating characteristic curve analysis showed that the optimal cut-off point of VAS score difference was 3.45 in predicting the pain onset, with sensitivity of 100% and specificity of 81.8%. ConclusionFor the fatigue induced test, the fatigue VAS score difference may predict the induced pain, and RMS difference associate with the occurrence of pain. No significant is observed of the Borg Fatigue Scale and PPT.

Key words: fatigue induced test, muscle fatigue, pain, surface electromyography, young women