不同体位下指压不同穴位对脑卒中患者胫前肌和腓骨长、短肌的表面肌电影响

摘要 目的：优化指压穴位刺激法在脑卒中偏瘫治疗中的应用。 方法：30例偏瘫患者,分别在仰卧伸膝0°位和屈膝90°位下指压偏瘫侧足三里、足临泣穴,对比刺激即刻3s、停止刺激后第一个3s、第二个3s、第三个3s的胫前肌和腓骨长、短肌最大等长收缩的积分肌电值（iEMG）。 结果：①刺激前后比较：两种体位下,指压两个穴位,刺激即刻的iEMG明显高于刺激前（P<0.05）,停止刺激后的三个3s的iEMG呈逐渐下降趋势。②穴位间比较：两种体位下,均表现为指压足三里穴,胫前肌刺激即刻的iEMG、停止刺激后的三个3s的iEMG均明显高于足临泣穴（P<0.05）;指压足临泣穴,腓骨长、短肌刺激即刻的iEMG、停止刺激后的三个3s的iEMG均明显高于足三里穴（P<0.05）。③体位间比较：仰卧屈膝90°位指压两个穴位,胫前肌刺激即刻、停止刺激后第一个3s的iEMG明显高于伸膝0°位（P<0.05）;腓骨长、短肌刺激即刻的iEMG明显高于伸膝0°位（P<0.05）。 结论：①指压刺激偏瘫侧足三里、足临泣穴均可诱发偏瘫侧胫前肌和腓骨长、短肌收缩,且即刻效应和延续效应良好。②指压足三里穴对诱发胫前肌收缩的即刻效应和延续效应优于足临泣穴;指压足临泣穴对诱发腓骨长、短肌收缩的即刻效应和延续效应优于足三里穴。③仰卧屈膝90°位,指压刺激足三里、足临泣穴对诱发胫前肌和腓骨长、短肌收缩的即刻效应明显优于伸膝0°位,延续效应无明显差异。     

Lower Extremity and Trunk Electromyographic Muscle Activity During Performance of the Y-Balance Test on Stable and Unstable Surfaces

BackgroundThe Star Excursion Balance Test (SEBT) has been used as a rehabilitation exercise. To improve its efficacy, efficiency, and method variations, the Y-Balance Test (YBT) with anterior (A), posterolateral (PL), and posteromedial (PM) directions of the SEBT has been recommended. Electromyographic activity has been reported to change when the same task is performed on various surfaces.Hypothesis/PurposeTo compare the EMG activity of trunk and LE muscles during the performance of the YBT on stable and unstable surfaces.Study DesignCross-Sectional study.MethodsHealthy adults with no history of chronic ankle instability were recruited for the study. Surface electromyography was collected for bilateral (ipsilateral [i] and contralateral [c]) rectus abdominis (RA), external oblique (EOB), erector spinae (ES). While, gluteus maximus (GMAX), gluteus medius (GMED), medial hamstrings (MH), biceps femoris (BF), vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), anterior tibialis (AT), and medial gastrocnemius (MG) on the stance leg (ipsilateral side), during the performance of the YBT. The unstable surface was introduced using a Thera-Band stability trainer. Differences in electromyography were examined for each reach direction and muscle between the stable and unstable surfaces (p≤ 0.05).ResultsTwenty (10 male, 10 female) subjects participated (age: 27.5 ± 4.0 years, height:167 ± 1.0 cm, weight: 66.5 ± 13.0 kg, body fat: 14.1 ± 6.2%). Significantly higher muscle activity for the unstable surface (p<0.05) with moderate to large effect sizes were observed for the following muscles in the A direction: GMED, GMAX, VM, RF, and MG; PL direction: iEOB, iES, cES, GMED, BF, VM, RF, and MG; and PM direction iEOB, iES, GMED, BF, VM, and RF. Significantly higher muscle activity for the stable surface (p = 0.007) was observed in MH muscle in the A direction. No significant differences (p>0.05) between the stable and unstable surfaces were observed in iRA, cRA, cEOB, VL, and AT for any of the directions of the YBT.ConclusionAn increase in muscle activity was observed during YBT on unstable versus stable surfaces for some muscles.Level of Evidence2B     

Interphase Effect on the Macro Nonlinear Mechanical Behavior of Cement-Based Solidified Sand Mixture

This paper investigates the interphase effect on the macro nonlinear mechanical behavior of cement-based solidified sand mixture (CBSSM) using a finite element numerical simulation method. CBSSM is a multiphase composite whose main components are soil, cement, sand and water, often found in soft soil foundation reinforcement. The emergence of this composite material can reduce the cost of soft soil foundation reinforcement and weaken silt pollution. Simplifying the CBSSM into a three-phase structure can efficiently excavate the interphase effects, that is, the sand phase with higher strength, the cement-based solidified soil phase (CBSS) with moderate strength, and the interphase with weaker strength. The interphase between aggregate and CBSS in the mixture exhibits the weak properties due to high porosity but gets little attention. In order to clarify the mechanical relationship between interphase and CBSSM, a bilinear Cohesive Model (CM) was selected for the interphase, which can phenomenologically model damage behaviors such as damage nucleation, initiation and propagation. Firstly, carry out the unconfined compression experiments on the CBSSM with different artificial gradations and then gain the nonlinear stress–strain curves. Secondly, take the Monte Carlo method to establish the numerical models of CBSSM with different gradations, which can generate geometric models containing randomly distributed and non-overlapping sand aggregates in Python by code. Then, import the CBSSM geometric models into the finite element platform Abaqus and implement the same boundary conditions as the test. Fit experimental nonlinear stress–strain curves and verify the reliability of numerical models. Finally, analyze the interphase damage effect on the macroscopic mechanical properties of CBSSM by the most reliable numerical model. The results show that there is an obviously interphase effect on CBSSM mechanical behavior, and the interphase with greater strength and stiffness ensures the macro load capacity and service life of the CBSSM; a growth in the interphase number can also adversely affect the durability of CBSSM, which provides a favorable reference for the engineering practice.     

Anterior and posterior neck muscle activation during a variety of biting tasks

Bruxism may be involved in the aetiology of myofascial neck pain. The objective of this study was to test the hypothesis that anterior and posterior neck muscles co-contract during jaw clenching. Ten test subjects developed different feedback-controlled submaximum bite forces in a variety of bite-force directions by means of bite-force transducers. The electromyographic activity of the sternocleidomastoid and supra/infrahyoidal muscles, and of the semispinalis capitis, semispinalis cervicis, and multifidi muscles was recorded by use of surface electrodes and intramuscular wire electrodes, respectively. For normalization of electromyography data, maximum voluntary contraction tasks of the neck muscles were conducted in eight different loading directions. The results confirmed co-contraction of the neck muscles in the range of 2-14% of the maximum voluntary contraction at a bite force ranging from 50 to 300 N. Significant activity differences were observed as a result of the different force levels and force directions exerted by the jaw muscles. Long-lasting tonic activation of specific neck muscles triggered by the jaw-clenching tasks was also detected. These findings support the assumption of a relationship between jaw clenching and the activity of the neck muscles investigated. The low level of co-contraction activity, however, requires further study to elucidate possible pathophysiological interactions at the level of single motor units.     

The influence of peripheral arterial disease on lower limb surface myoelectric signals in patients living with type II diabetes mellitus

BackgroundThe aim of this study was to evaluate whether there are any significant differences in muscle activity between individuals living with type II diabetes mellitus (T2DM) and individuals living with T2DM and peripheral arterial disease (PAD), during gait at a self-selected speed. The influence of different stages of PAD on muscle activity during gait was also assessed with the use of surface electromyography (EMG).Research questionDoes PAD affect lower limb muscle activity during gait in the presence of T2DM?MethodsThis quantitative study involves a prospective, comparative, non-experimental subject design. Ninety participants were divided into three groups namely Group A (thirty participants living with T2DM), Group B(i) (thirty participants living with T2DM and mild PAD) and Group B(ii) (thirty participants living with T2DM and severe PAD). Surface electrode sensors were placed according to SENIAM guidelines, on six main lower limb muscles on both limbs. Muscle activity was recorded using a wireless system, where participants were instructed to walk at a self-selected speed on a 10-m walkway. Average Burst RMS was performed and the amplitude (mV) and the duration of muscle activation (s) was analysed.ResultsThere was a significant increase in muscle amplitude and duration of activation in the presence of lower limb ischaemia during gait. The largest significant difference (p = <0.05) in EMG amplitude and duration of activation when looking at the twelve muscles in general was found between participants living with T2DM and participants living with T2DM and severe PAD.SignificanceThe increase in muscle activity indicates that there are musculoskeletal and biomechanical changes in the lower limb musculature with increasing severity of PAD. Higher muscle exertion demands are required during gait which may result in earlier fatigue. EMG tests would be beneficial for detecting muscle dysfunction objectively and non-invasively in T2DM and PAD.     

膝关节骨性关节炎推拿手法的力学特征和上肢核心肌群的疲劳研究

探讨膝关节骨性关节炎推拿手法的生物力学特征和生理学(表面肌电)特征,定量分析推拿手法的力学指标,建立一种客观评价推拿医生上肢核心肌群的疲劳状况的方法。招募10位推拿科医生,实时采集推拿医生拇指垂直压力和上肢表面肌电信号,研究垂直强度、次做功期与主做功期的时间比;研究操作该推拿手法时的上肢核心肌群;研究核心肌群的疲劳状况。结果表明,该推拿手法1 min内按压4次,平均垂直强度为(228±13)N,主做功期持续时间为(4.83±0.88)s,次做功期持续时间为(11.43±1.94)s,有效做功时间比为2.37±0.63。由上肢各肌肉群的平均积分肌电值(iEMG)和贡献率的降序可知,手法涉及上肢的核心肌群为拇短展肌(8.32±0.29,21.65%)、尺侧腕屈肌(5.67±0.32,14.74%)、肱三头肌(4.79±0.36,12.46%)、桡侧腕屈肌(4.60±0.12,11.96%)。在4 min的推拿过程中,拇短展肌的平均中值频率(MF)和平均功率频率(MPF)的下降程度是最大的,分别为30%和22%,即拇短展肌更易发生疲劳。因此,所研究的膝关节骨性关节炎推拿手法的生物力学特征和生理学(表面肌电)特征,为后续的人因工程研究和研制可替代推拿医生手法的自动化装置奠定良好的基础。     

咬合板治疗肌筋膜痛效果评估－随机双盲对照实验

Background Occlusal splints have been the preferred modalities in the management of myofascial temporomandibular disorders (TMDs),but now controversy exists in reporting whether they are successful for...