Comparative study of surface electromyography of masticatory muscles in patients with different types of bruxism

BACKGROUND Bruxism is a rhythmic masticatory muscle activity that occurs involuntarily in a non-physiologically functional state.There is a lack of research classifying the functional status of masticatory muscles in patients with different mandibular movement types(centric clenching or eccentric grinding)of bruxism.AIM To assess the differences of the masticatory muscle activity in patients with different types of bruxism.METHODS A total of 21 subjects with centric bruxism(CB)and 21 subjects with eccentric bruxism(ECB)were screened from college students according to a questionnaire and their tooth wear features.Sixteen subjects with no bruxism were also recruited.The surface electromyography(EMG)signals of the temporalis anterior(TA)and superficial masseter muscle(MM)were measured in different mandibular positions and during the chewing task.The EMG amplitude and chewing cycle duration parameters were then analyzed.RESULTS The CB group showed fewer muscle maximal motor units,with the MM being more pronounced,a higher proportion of muscle contractions to be recruited for the same load of chewing activity,and a longer chewing cycle.The ECB group showed more TA maximal motor units and higher MM activity on the nonworking side in unilateral chewing.CONCLUSION CB mainly affects the MM,and patients with CB show reduced masticatory muscle contraction efficiency and chewing cycle efficiency.ECB mainly affects the TA,and patients with ECB show enhanced contraction of non-functional lateral muscle bundles.

Diagnostic value of orbicularis oculi muscle electromyography in functional epiphora

BACKGROUND Functional epiphora is a clinical condition which is not due to an anatomic defect.Most studies agree that it involves the action of the orbicularis oculi muscle,particularly its deeper segment(Horner’s muscle),but the exact mechanism is not clear.AIM To evaluate the orbicularis oculi muscle in functional epiphora patients using electromyography(EMG).METHODS A total of 8 Chinese patients(16 eyes)with functional epiphora were enrolled in this study,and ten volunteers(10 eyes)were included as normal controls.Five epiphora patients(five eyes)with facial palsy served as positive controls.Quantitative EMG was performed in the deeper segment of orbicularis oculi muscle.The average duration of each EMG waveform was measured.RESULTS The average duration of EMG waveforms in the normal control group,the functional epiphora group,and the facial palsy group were 6.39±0.73 ms,9.39±1.32 ms and 11.2±1.42 ms,respectively.The duration of EMG waveforms was significantly longer in the functional epiphora group than in the normal control group(P<0.05),and shorter than that in the facial palsy group(P<0.05).CONCLUSION These data indicate the presence of neurogenic orbicularis oculi muscle damage in epiphora patients,which may be the cause of functional epiphora.The etiology of neurogenic damage in the orbicularis oculi muscle requires further investigation.

Custom-Made Mouthguards: Electromyographic Analysis of Masticatory Muscles and Cardiopulmonary Tests in Athletes of Different Sports

The purpose of this study is to analyse the neuromuscular balance of the masticatory muscles and the influence on the athlete respiratory parameters induced by custom-made mouthguard. Twenty-six athletes (24 males and 2 females), of different disciplines, average age of 32.12 ± 12.05, were recruited. Each athlete received a custom-made mouthguard in the Ethylene-Vinyl-Acetate (EVA) thermoplastic material and using surface electromyography, the masseter muscles and the frontal beams of the temporal muscles were analysed, with and without mouthguard. The athletes were then subjected to a medical examination and cardiopulmonary test, in the condition with and without mouthguard. The use of mouthguard caused an improvement of all the electromyographic indexes analysed. In particular, GLOBAL INDEX (p = 0.0021), BAR (p = 0.0005), IMPACT (p = 0.0076) and ASIM (p = 0.0290) showed an enhancement statistically significant. For the cardiopulmonary test indexes as maximum oxygen uptake (VO2max), minute ventilation (VE), breathing reserve (BR), not statistically differences (p > 0.05) were reported. The custom-made mouthguard improved the neuromuscular balance of the masticatory muscles, symmetrizing the masseters and temporalis muscles work. It produced a better balancing distribution of occlusal loads both in the anterior-posterior direction and in the lateral direction and offered the possibility to produce more muscular work. Moreover, it did not constitute an impediment that can significantly disturb the athlete’s breathing during physical activity.

Real-time surface electromyography in Parkinson's disease patients during exercise-induced muscle fatigue

To explore the mechanisms underlying exercise-induced local muscle fatigue in patients with idiopathic Parkinson＇s disease （PD）,we used surface electromyography to record myoelectric signals from the tibialis anterior muscle during isometric contraction-induced fatigue until exhaustion.The results revealed no significant differences between patients with idiopathic PD and healthy controls in maximum voluntary contraction of the tibialis anterior muscle.The basic characteristics of surface electromyography were also similar between the two groups.The duration of isometric contraction at 50% maximum voluntary contraction was shortened in PD patients.In addition,PD patients exhibited a stronger increase in mean square amplitude,but a weaker decrease in median frequency and mean power frequency compared with healthy controls during isometric contraction.The skeletal muscles of PD patients revealed specificity of surface electromyography findings,indicating increased fatigability compared with healthy controls.

Effects of Compression Garments on Lower Limb Muscle Activation via Electromyography Analysis during Running

Sports compression garments are common-selected sportswear to improve athletic performance and reduce sports injury. Since they consist of elastic textile that exerts compression and pressure onto the muscle,muscle activation is of interest to sports compression garment manufactures who seek to enhance sports performance through gradient compression garment design.However,there are few scientific investigations to explore this effect of muscle activation to evaluate the performance of sports compression garments during sport activity. In this paper, a systemic experimental protocol was presented to improve the quality of evaluation test under a standardized running test. Then muscle activation with and without wearing sport compression garments to highlight the changes caused by compression garment was investigated. The electromyography( EMG) signal was collected and processed by the proposed method to represent the muscle activation combined with gait analysis of running. As a result,the average muscle activation of gait cycle for the major muscles such as rectus femoris( RF) and gastrocnemius medialis( GM) revealed that they needed to exert more muscle force without wearing garment at certain periods for mid-stand and pre-swing phase within gait cycle. These lower muscle activation levels prolonged activity duration,reduced fatigue,and presented low risk for sport injury.Such an evaluation study therefore would scientifically prove the effect of compression garment and provide information on muscle activation and the ergonomic efficacy of gradient compression garment design.

不同方式shaker训练过程中健康成人舌骨肌群激活程度的差异

背景:Shaker训练可增强舌骨肌群的收缩力,对口咽性吞咽障碍的治疗效果显著。Shaker训练应通过颈前部主要发力以达到训练舌骨肌群的目的,但患者常因疲劳易导致腹部发力代偿,不同发力方式的shaker训练对健康成人舌骨肌群激活程度的影响目前尚不明确。目的:探讨不同发力方式的shaker训练对健康成人舌骨肌群激活程度的影响。方法:纳入20名健康成人受试者(男10名、女10名),平均年龄为(26.8±3.4)岁。使其按照顺序分别采用颈前部与腹部主要发力进行shaker训练的等长运动,同时实时采集舌骨上、下肌群及腹直肌活动的表面肌电信号,并在训练结束后采用Borg自觉疲劳量表对每种发力方式的疲劳程度进行评估。对原始肌电信号进行一系列处理后,计算舌骨上、下肌群和腹直肌在60 s运动窗口内的峰值振幅和/或平均振幅值并进行对比分析,同时比较两种发力方式所对应主观疲劳评分的差异。结果与结论:①腹部发力所对应腹直肌平均振幅值高于颈部发力(P<0.05);②两种发力方式相比,舌骨上肌群的平均振幅、峰值振幅以及舌骨下肌群的平均振幅、峰值振幅均未见显著差异(P>0.05),Borg自觉疲劳量表评分在两种发力方式之间亦未见显著差异(P>0.05);③结果提示,不同发力方式(颈前部和腹部)的shaker训练对健康成人舌骨肌群激活程度的影响没有显著差异,且疲劳感相似。

下肢重复蹬伸至力竭过程中肌肉功能网络拓扑特性

背景:表面肌电已经被广泛用于监测肌肉疲劳,但传统肌电指标通常针对于单块肌肉,无法评价一组肌肉在疲劳过程中的变化。目的:建立肌肉功能网络,提取复杂网络参数,研究不同疲劳程度下的肌肉功能网络拓扑特性变化,为疲劳的监测、预防提供理论和方法依据。方法:11名受试者进行直到力竭的50%1RM单腿下肢蹬伸运动,同步采集股直肌、股外侧肌、股内侧肌、股二头肌长头、胫骨前肌、腓肠肌外侧肌、腓肠肌内侧肌7块肌肉的肌电信号,以及心电信号和Borg CR-10量表评分;根据Borg CR-10量表评分划分为轻度、中度和重度三个疲劳阶段,采用心率和心率变异性验证疲劳阶段划分的有效性;以7块肌肉为节点,使用肌肉信号的相干性构建肌肉功能网络,提取聚类系数、平均加权度、全局效率、特征向量中心性4个复杂网络参数;提取肌电信号的均方值振幅、中位频率、瞬时平均频率和共激活比4种指标,并在3种疲劳程度下进行比较。结果与结论:①3种疲劳阶段在心率及心率变异性上产生显著性差异,证明了疲劳阶段划分的有效性;②对于不同肌肉在3种疲劳程度下的肌电指标:均方值振幅和共激活比未表现出差异,中位频率在股外侧肌、股内侧肌和股二头肌长头表现出稳健的疲劳趋势,瞬时平均频率则在股直肌、股外侧肌、股内侧肌和股二头肌长头表现出稳健的疲劳趋势;瞬时平均频率的性能优于中位频率和均方值振幅,但三者仅在主要工作肌群能够获得较好的稳健趋势,共激活比不受疲劳因素的影响;③股外侧肌-股内侧肌、股外侧肌-股二头肌长头、股外侧肌-腓肠肌内侧肌和股内侧肌-股二头肌长头连接强度逐渐增加,平均加权度、聚类系数和全局效率在疲劳后表现出显著差异,并且与疲劳程度之间显著相关。结果表明:肌肉功能网络内的连通强度变化能够反映疲劳过程中肌肉间的协同性和互补性;聚类系数、平均加权度、全局效率可作为一组肌肉疲劳的监测指标。

基于肝肾同源理论探讨肌筋膜触发点拔罐对腰椎间盘突出症的影响

目的基于肝肾同源理论探讨肌筋膜触发点拔罐对肝肾亏虚型腰椎间盘突出症患者腰椎功能及腰背伸肌群表面肌电指标的改善效果。方法选取河南省中医院骨科2022年3月至2024年3月收治的109例肝肾亏虚型腰椎间盘突出症患者作为研究对象,对照组54例给予CT引导下射频针刀联合脊得舒丸治疗,观察组55例在对照组基础上增加肌筋膜触发点拔罐,对比两组患者中医证候积分、腰椎功能、腰椎活动度、腰背肌表面肌电信号的变化、复发率及不良反应。结果治疗后,两组中医证候评分均降低(P<0.05),且观察组更低(P<0.05)。治疗后,两组腰椎功能评分及活动度均增加(P<0.05),且观察组更高(P<0.05)。治疗后,两组积分肌电值及平均功率频率均增加(P<0.05),且观察组更高(P<0.05)。观察组复发率3.70%低于对照组18.52%(P<0.05)。两组不良反应差异无统计学意义(P>0.05)。结论基于肝肾同源理论的肌筋膜触发点拔罐能够减轻肝肾亏虚型腰椎间盘突出症患者临床症状,改善腰椎功能,调节腰背伸肌群表面肌电,并降低复发率。

A Novel Estimating Method for Steering Efficiency of the Driver with Electromyography Signals

The existing research of steering efficiency mainly focuses on the mechanism efficiency of steering system, aiming at designing and optimizing the mechanism of steering system. In the development of assist steering system especially the evaluation of its comfort, the steering efficiency of driver physiological output usually are not considered, because this physiological output is difficult to measure or to estimate, and the objective evaluation of steering comfort therefore cannot be conducted with movement efficiency perspective. In order to take a further step to the objective evaluation of steering comfort, an estimating method for the steering efficiency of the driver was developed based on the research of the relationship between the steering force and muscle activity. First, the steering forces in the steering wheel plane and the electromyography （EMG） signals of the primary muscles were measured. These primary muscles are the muscles in shoulder and upper ann which mainly produced the steering torque, and their functions in steering maneuver were identified previously. Next, based on the multiple regressions of the steering force and EMG signals, both the effective steering force and the total force capacity of driver in steering maneuver were calculated. Finally, the steering efficiency of driver was estimated by means of the estimated effective force and the total force capacity, which represented the information of driver physiological output of the primary muscles. This research develops a novel estimating method for driver steering efficiency of driver physiological output, including the estimation of both steering force and the force capacity of primary muscles with EMG signals, and will benefit to evaluate the steering comfort with an objective perspective.

Quantitative features of myoelectric signals in the orbicularis oculi muscle during different motion states

Artificial facial nerve prostheses are thought to restore eye-closed function in peripheral facial paralysis patients.At present,however,there is no adequate quantitative or qualitative information regarding myoelectric signal（MES）features for healthy orbiculads oculi muscle（OOM）.The present study analyzed MES features of normal OOM in rabbits during the natural continuous eye-opening（N1）state,natural continuous eye-closing（N2）state,natural blink（N3）state,and evoked eye-closing（E）state according to time domain and frequency domain analysis.Results showed that OOM electrical activities in N1 and N2 states,as well as myoelectric amplitude,were low and stable.Nevertheless,during N3 and E states,OOM electrical activities were significantly increased and amplitude was much higher in the E state than in the N3 state.In the time domain,differences in MES peak absolute potential were not significant between N1 and N2 states,in the frequency domain,differences in power spectral density peak frequency of electromyogram signals were significant between two sets of four OOM movement states.These results suggest that OOM significantly contracts and induces eyelid-closing action.In addition,OOM is diastolic during the N1state.A N2 state does not require continuous intensive OOM contraction.Moreover,distinctions of quantitative information in time and frequency domain features of MES can be used as an OOM reference to identify muscle movement patterns.

Quantification of the Pain and Physical Burden Experienced during Positioning for Craniocaudal Imaging in Mammography, Evaluated by Measurement of Muscle Activity

Mammography is carried out in a special position, i.e. “an image is taken while the breast is compressed, stretched and kept in a fixed position”. The purpose of this study was to demonstrate quantitatively and qualitatively the physical and psychological burden due to positioning and breast compression during mammography. Muscle activity of each part of the body during positioning for the standard imaging method, to obtain craniocaudal (CC) view images, was measured in 15 adult females using surface EMG. The associated pain was analyzed using visual analogue scale (VAS) scores. During positioning for the CC view, muscle activity was highest in the biceps (24.44 iEMG/s) followed by the trapezius (17.78 iEMG/s) on the imaging side. Muscle activity of the biceps and the sternocleidomastoid on the imaging side showed significant differences compared with pre-imaging activity (biceps P < 0.031, sternocleidomastoid P < 0.005). The pain during mammography was rated as moderate to severe pain (VAS = 3.3 - 6.7) for CC views. As a result, the activities of not only the muscles directly involved in mammography positioning but also those indirectly involved were high as compared with the normal state. Measurement of muscle activity during mammography is expected to be used effectively, such as in the care to reduce pain for the subjects.

Electromyographic study of shoulder and acromioclavicular joint muscles in women who underwent unilateral breast surgery of the types mastectomy and quadrantectomy

We studied 20 women with mean age 57.7 years, being 9 with unilateral quadrantectomy surgery, 1 with surgery type bilateral quadrantectomy and 10 with unilateral mastectomy surgery. The average operative time was 9.8 (nine years and eight months). We studied using surface electromyography the mean deltoid, upper trape-zius and latissimus dorsi muscles in order to check the action potentials of these muscles when performing a sequence of movements of these joints. It was used for the study, an Acquisition Data System ADS1000 containing 12 channels. The electromyography (EMG) results expressed in RMS (Root Mean Square) were analyzed and compared between the surgical and nonsurgical side, among the three repetitions of the sequence of movements and between mastectomy and quadrantectomy for each muscle. For statistical analysis we used analysis of variance (ANOVA) with a double repetition factor

Reliability Study on Quantitative Detection of Extensor Digi- torum Brevis Strength with Needle Electromyography and Nerve Conduction

Objective To study the objectivity and reliability of needle electromyography and nerve conduction for detection of musculus extensor digitorum brevis strength, which may provide a basis for establishing a quantitative detection of muscle strength in forensic clinical study. Methods Forty-four healthy people were enrolled as the subjects, and during toe dorsiflexion, the following items including needle electromyography indexes, motor unit potential(MUP) amplitude, MUP count, recruitment reaction type, and nerve conduction detection indexes, compound muscle action potential(CMAP) amplitude, CMAP latent period and motor nerve conduction velocity(MNCV), were simultaneously detected under the cooperation and disguise condition. Results Under the cooperation condition, regardless of the same operator or different operators, there were good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, while there were normal test-retest reliabilities in MUP count and recruitment reaction type and the repeatability of the same operator was slightly better than the repeatability between different operators. Under the disguise condition, test-retest reliabilities of MUP amplitude, CMAP amplitude, CMAP latent period and MNCV were relatively high, while test-retest reliabilities of MUP count and recruitment reaction type were relatively low. Conclusion There are good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, which can be conducive to comparison between different operators and results at various times; MUP count and recruitment reaction type, which can be easily affected by subjectivity of operators and examinees, can be used to differentiate whether an examinee disguises or not. The indexes used to objectively judge muscle strength remain to be further investigated.

Electromyographical Study on Muscle Fatigue in Repetitive Forearm Tasks

The purpose of this study was to examine whether repetitive muscle tasks in low weight load might influence the fatigue of forearm muscles, and to identify ergonomic risk factors of forearm muscle fatigue in these tasks. Sixteen healthy male volunteers performed eight wrist extensions in different frequency, weight and angle loads while being instructed to keep a dominant upper limb posture as constant as possible. Surface electromyograph （sEMG） was recorded from right extensors digitorium （ED）, flexor carpi radialis （FCR）, flexor carpi ulnaris （FCU） and extensor carpi ulnaris （ECU） during the task performance. Our results showed that mean power frequency （MPF） and median frequency （MF） values of ED, FCR and FCU were significantly lower （P〈0.05） at high frequency load level than at low load level. However, MPF and MF values of ED were significantly lower （P〈0.01） in higher load groups of frequency, angle and weight than in lower load groups. These results indicated that the fatigue of muscles varied in the same task, and the number-one risk factor of ECU, ED and FCR was angle load.

Barefoot and High-Heeled Gait: Changes in Muscles Activation Patterns

Most women like wearing high-heeled shoes for the benefit of sensuous attractiveness and self-esteem while musculoskeletal problems and gait patterns changes are often associated. The present study aimed to identify changes during the gait stance and swing phases in some lower limb muscles. In addition, abdominal muscle was included due to its importance in dynamic trunk stability, and lack of studies on the subject. Here, we found that the use of high-heeled shoes elicited not only the increasing of the electrical activity from the muscles involved in the gait cycle, but also altered the temporal sequence of their recruitment. As practical applications, these changes may be strategies to maintain stability and minimize risks of falling, but they are often associated to diseases. Women that use high-heeled shoes for prolonged time must apply specific muscle exercises to minimize its long-term effects.

Systematic reduction of leg muscle activity throughout a standard assessment of running footwear

Purpose This study aimed to investigate whether there is a systematic change of leg muscle activity,as quantified by surface electromyography(EMG),throughout a standard running footwear assessment protocol at a predetermined running speed.Methods Thirty-one physically active adults(15 females and 16 males)completed 5 testing rounds consisting of overground running trials at a speed of 3.5 m/s.The level of muscle activity from 6 major leg muscles was recorded using surface EMG.The variables assessed were the EMG total intensity as a function of time and the cumulative EMG overall intensity.Systematic effects of the chronological testing round(independent variable)on the normalized EMG overall intensity(dependent variable)were examined using Friedman analysis of variates and post hoc pairwise Wilcoxon signed-rank tests(α=0.05).Results There was a systematic reduction in overall EMG intensity for all 6 muscles over the time course of the running protocol(p<0.001)until the fourth testing round when EMG intensities reached a steady state.The one exception was the biceps femoris muscle,which showed a significant reduction of EMG intensity during the stance phase(p<0.001)but not the swing phase(p=0.16).Conclusion While running at a predetermined speed,the neuromuscular system undergoes an adaptation process characterized by a progressive reduction in the activity level of major leg muscles.This process may represent an optimization strategy of the neuromuscular system towards a more energetically efficient running style.Future running protocols should include a familiarization period of at least 7 min or 600 strides of running at the predetermined speed.

Reliability of Power Spectral Analysis of Surface Electromyogram Recorded during Sustained Vastus Medialis Isometric Contraction in Assessment of Muscle Fatigability

The aim of this study was to determine the within-day and between-days reliability of surface electromyographic (EMG) power spectral analysis in assessing fatigability of the vastus medialis (VM) muscle during knee and hip flexion under constant load application. The subjects were 13 healthy adult men free of knee abnormalities. Surface EMG was recorded from vastus medialis obliquus (VMO) and vastus medialis longus (VML) during sustained isometric contractions at 60% of maximal voluntary contraction until exhaustion on the leg press machine (static leg press test). Linear regression analysis was applied to median frequency (MF) time series to calculate initial MF and MF slope. For VMO and VML, the initial MF showed moderate to high reliability, while the MF slope showed high reliability (Intraclass correlation coefficient (ICC) = initial MF: 0.63 - 0.92, MF slope: 0.70 - 0.86). The results demonstrated that spectral analysis of surface EMG recording during isometric VM muscle contraction has high within-day and between-days reliability in the assessment of fatigability of the VMO and VML.

Electromyography Control of a Computer Model of the Arm

Human arm movements may be adversely affected in the event of stroke or spinal cord injuries, eventually causing the patient to lose control of arm movements. Electromyography (EMG) is con-sidered the most effective technique for the restoration of arm movement in such cases. The reha-bilitation period for such patients is usually long. Moreover, complex treatment techniques may demoralize them. Therefore, this study, attempts to contribute to the development of a relaxing rehabilitation environment through electromyography control of a computer model of the arm. The model is created using MATLAB? and Data LINK software and other requisite components for training the targeted participants to control their arm movements. Six male participants with no history of injury to the arms or back were selected using the set protocol. The results and data collected are analysed using three performance measures i.e. the number of target hits, average time to target, and path efficiency for each target. Then, the main results in terms of the obtained performance measures are discussed and compared with those of previous studies.

changes in muscle activity in patients with primary chronic headache

Objective:According to the Global Burden of Disease Study,updated in 2018,headache disorders are the second leading cause in the world and impaired quality of life and lead to reduce daily activity and can be the cause of headache-related disability.So,we desperately need to develop new painless and minimally invasive methods to facilitate diagnosis to improve the quality of headache care.Methods:Our study involved 92 participants over 18 years of age with a diagnosis of primary chronic headache.Among those,36 were with chronic tension type headache,26 were with a chronic migraine,and 30 were healthy participants.All patients were selected according to the criteria of the International Headache Society.Clinical questionnaires,instrumental data,and characteristics of headache episodes were collected from all participants.We evaluated the muscle activity of the pericranial and cervical muscles in patients with chronic headache to compare with healthy participants using Surface electromyography to determine if there is an alteration in muscle activity.Results:Surface electromyography data showed that there was a statistically significant difference in results between the target group and the control group,where patients with primary chronic headache had high amplitude and velocity in the studied muscles on the electromyogram.Among the participants,there was a difference in the intensity of headache attacks on the visual analog scale chronic tension type headache 5.2±1.4,chronic migraine 7.7±1.3,control group 1.6±0.7 and in the frequency of headache attacks per month chronic tension type headache 14.4±1.9,chronic migraine 17.3±2.9,the control group of participants had headache attacks of≤1 per month.Conclusion:We concluded that the patients with primary chronic headaches there are changes in the muscle activity of the pericranial and cervical muscles.In contrast to patients without chronic headaches,which,in turn,the method of surface electromyography may encourage further research in this area.

Back Muscle Electromyographic Changes in Rehabilitation of Occupational Low Back Pain

This study is to investigate the changes of back muscle electromyography (EMG) in occupational low back pain (LBP) patients pre-and post-rehabilitation.20 occupational LBP patients were asked to perform sepcially designed symmetrical and asymmetrical actions,which include"carrying"weights up and down with a 45° left rotation.Back muscle EMG signals were recorded from surface of paraspinal muscles.The tests performed in the weeks immediately before and after 12-week rehabilitation treatment.The profile and mean power frequency (MPF) of EMG were compared between pre-and post-rehabilitation.EMG profiles showed unchangeable,but the MPF showed significantly increase in post-rehabilitation comparing to pre-rehabilitation.That suggested that the muscle activity strategies could not be modified by rehabilitation,but the rehabilitation would increase the threshold of fatigue and reduce the possible muscle pain in back paraspinal muscles.