Effect Of Whole Body Vibration Exercise On Activation Time Of Core Muscles In Patients With Nonspecific Low Back Pain

Background: Nonspecific low back pain(NSLBP)is a ubiquitous worldwide pain problem that is one of the most costly and dysfunctional problems of all health issues.Whole body vibration(WBV)exercise is a non-pharmaceutical,non-invasive intervention that has become an increasingly popular way to treat low back pain.It is reported that a strong relationship between core muscles neuromuscular function and non-specific low back pain.However,whether WBV can improve the core muscle function of NSLBP patients remains controversial.Thus,we conducted a cross-sectional study,and a randomized controlled study to determine the effects of WBV exercise on activation time of core muscles in NSLBP patients,and provide theoretical basis for the clinical application of whole body vibration training in NSLBP.It reveals the mechanisms of which core stability exercise relieves pain for NSLBP.Study 1 cross-sectional study: changes in activation time of core muscles in patients with nonspecific low back painObjective: To investigate the difference in activation time of core muscles activity during standing sagittal imbalance and coronal imbalance for individuals with and without NSLBP.Methods: 40 NSLBP patients and 41 normal volunteers participated in this study.Participants completed the right upper limb resistance flexion(sagittal imbalance)and resistance abduction(coronal imbalance)at the fastest speed in the standing position and repeated 3 times.Surface electromyography(s EMG)signals were recorded from the right anterior deltoid,right middle deltoid,bilateral erector spines,bilateral multifidus,bilateral rectus abdominis and bilateral transversus abdominus/internal oblique muscles.The relative activation time between each muscle and the prime mover(i.e.,the anterior deltoid for upper limb flexion,middle deltoid for abduction)were calculated.A positive value indicated that the target muscle fired after the prime mover,and vice versa.The differences in relative activation times between the two groups were compared.Results: In sagittal imbalance,muscles in the NSLBP group were activated after anterior deltoid,the onsets of the bilateral erector spines,bilateral multifidus,bilateral transversus abdominus/internal oblique muscles were significantly delayed in the NSLBP group compared with the normal group(P<0.05),and the relative activation time of bilateral rectus abdominis in NSLBP group were not significantly different from that of the normal group(right: P=0.112,left: P=0.035).Averaged bilaterally for back and abdominal muscle groups,the relative activation time of the back and abdominal muscles in the NSLBP group was significantly delayed than that in the normal group(back: t=3.405,P=0.001;abdominal: t=3.378,P=0.001).In coronal imbalance,muscles in the NSLBP group and normal group were activated after middle deltoid.The onsets of the bilateral erector spines,bilateral multifidus,right transversus abdominus/internal oblique muscles and right rectus abdominis were significantly delayed in the NSLBP group compared with the normal group(P<0.05).Averaged bilaterally for back and abdominal muscle groups,the relative activation time of the back muscles in the NSLBP group was significantly delayed than that in the normal group(t=7.752,P<0.001)Conclusion: Individuals with NSLBP has delayed activation of the back and abdominal core muscle groups during sagittal imbalance and delayed activation of back core muscle groups during coronal imbalance.Study 2 a single treatment randomized controlled study: effect of whole body vibration exercise on activation time of core muscles in patients with nonspecific low back painObjective: To determine the effect of a single treatment of whole body vibration(WBV)exercise on muscle activation time of core muscles in NSLBP patients.Methods: 40 participants with NSLBP were randomly divided into the WBV group(n=20)and the control group(n=20).The WBV group was arranged to a single treatment of WBV exercise,and the control group rested for the corresponding time.The s EMG signals of right anterior deltoid,right middle deltoid,bilateral erector spines,bilateral multifidus,bilateral rectus abdominis and bilateral transversus abdominus/internal oblique muscles were recorded before and after the intervention in the sagittal imbalance and coronal imbalance.The relative activation time of each muscle was calculated.Results: In WBV group,except for the right erector spinae,the relative activation time of each muscle decreased after intervention,and the relative activation time of the bilateral multifidus and bilateral transversus abdominus/internal oblique muscle were significantly decreased during sagittal imbalance(right multifidus: t=2.717,P=0.014;left multifidus: t=2.828,P=0.011;right transversus abdominus/internal oblique muscle: t=2.951,P=0.008;left transversus abdominus/internal oblique muscle: t=2.407,P=0.026).Compared with the control group,the relative activation time of the right transversus abdominus/internal oblique muscle and the left rectus abdominis muscle in WBV group were significantly less than that in the control group(right transversus abdominus/internal oblique muscle: t=-2.901,P=0.006;left rectus abdominis: t=-2.135,P=0.039).As for coronal imbalance,the relative activation time of each muscle decreased after intervention.except for left transversus abdominus/internal oblique muscles and left rectus abdominis,the relative activation time of other muscles were significantly reduced(right erector spines: t=3.847,P=0.001;left erector spines: t=4.641,P<0.001;right multifidus: t=4.093,P=0.001;left multifidus: t=2.093,P=0.009;right transversus abdominus/internal oblique muscle: t=5.239,P<0.001;right rectus abdominis: t=3.800,P=0.001).Compared with the control group,the relative activation time of left erector spines,right multifidus,right transversus abdominus/internal oblique muscle and right rectus abdominis in WBV group were significantly less than that in the control group(left erector spines: t=-2.496,P=0.017;right multifidus: t=-2.552,P=0.015;right transversus abdominus/internal oblique muscle: t=-3.113,P=0.004;right rectus abdominis: t=-3.984,P<0.001).Conclusion: The single treatment of whole body vibration exercise can effectively improve the delayed activation of core muscles in patients with nonspecific low back pain,but the long-term effects still need further study.