Recruitment order of the abdominal muscles varies with postural task

Abdominal muscle recruitment strategies in response to a postural perturbation contradict the theory that the deeper abdominal muscles are always recruited in advance of the more superficial muscles. The purpose of this study was to determine whether such contrasting muscle recruitment patterns are due to the postural task or the predictability of a postural task. Participants performed an arm raise task as well as an unpredictable and a predictable balance perturbation task (i.e. support‐surface translation) while intramuscular electromyographic (EMG) recordings were obtained from the deep [transversus abdominis (TrA)] and superficial [obliquus externus (OE)] abdominal muscles. The abdominal muscle recruitment order was dependent on the postural task but not on the predictability of a postural perturbation. Whereas arm raises elicited similar EMG onset latencies in TrA and OE, the OE onset latency was 48 ms earlier than the TrA following an unpredictable translation (P = 0.003). The early OE activation persisted when the translation was made predictable to the participant (P = 0.024). These results provide evidence that the abdominal muscle recruitment order varies with the trunk stability requirements specific to each task. Rehabilitation strategies focusing on an early TrA activation to improve postural stability may not be appropriate for all everyday tasks.     

一种刚度可调的前置式足下垂矫形器研制

目的 针对足下垂步态患者,设计一种刚度可调的前置式踝足矫形器(ankle foot orthosis,AFO),实现对患者踝关节病态跖屈的最佳限制以恢复踝关节自然步态的目的.方法 通过自制实验装置测得10名18～55岁肌肉无力导致足下垂男性患者畸形矫正所需的最小矫治力矩,应用于AFO材料选择.通过力学拉伸实验,研究不同...     

Clinical features and treatment of near-work-related acquired esotropia

AIM: To investigate the characteristics of near-work-related esotropia and the clinical efficacy of botulinum toxin type A (BTXA) injection therapy on it. METHODS: A total of 107 patients aged 15-57y with near-work-related esotropia were taken as the BTXA-treated group, and 30 other peers without near-work-related esotropia were included in the control group. All participants were refractive corrected to analyse the clinical characteristics of near-work-related esotropia. All subjects were examined including Worth4 spot examination, stereoscopic vision, strabismus angle, accommodative convergence to accommodation ratio (AC/A), far and near positive and negative convergence, positive and negative fusion range, positive and negative relative accommodation. Clinical efficacy was evaluated at a period of 10mo follow-up. RESULTS: The distant and near stereopsis were found in 84.9% and 77.5% of patients in the BTXA-treated group, respectively. In the control group, all patients had distant and near stereopsis. The incidence of taking off one’s glasses to see close objects was significantly higher in the BTXA-treated group than in the control group (P<0.05). The BTXA-treated group showed a smaller range of in-fusion (9.84±5.72)° than the control group (22.04±8.71)° (P<0.05). The near esotropia angle of the BTXA-treated group (17.08±11.98)△ was significantly smaller than the distant esotropia angle (19.07±11.68)△ (P<0.05). Ten months after injection, the diplopia and esotropia of most patients underwent improvements after treatment (P<0.05). CONCLUSION: This study reveals that the accommodation function and the habit of near work without wearing spectacles are associated with near-work-related esotropia, while the length of time for near work and the onset time are independent of near-work-related esotropia. Additionally, BTXA injection therapy plays a vital role in relieving diplopia and restoring eye position.     

ROLLER MASSAGER IMPROVES RANGE OF MOTION OF PLANTAR FLEXOR MUSCLES WITHOUT SUBSEQUENT DECREASES IN FORCE PARAMETERS

Background:

Limited dorsiflexion range of motion (ROM) has been linked to lower limb injuries. Improving limited ankle ROM may decrease injury rates. Static stretching (SS) is ubiquitously used to improve ROM but can lead to decreases in force and power if performed prior to the activity. Thus, alternatives to improve ROM without performance decrements are needed.

Objectives/Purpose:

To compare the effects of SS and self massage (SM) with a roller massage of the calf muscles on ankle ROM, maximal voluntary contraction (MVC) force F100 (force produced in the first 100 ms of the MVC), electromyography (EMG of soleus and tibialis anterior) characteristics of the plantar flexors, and a single limb balance test.

Methods:

Fourteen recreationally trained subjects were tested on two separate occasions in a randomized cross‐over design. After a warm up, subjects were assessed for passive dorsiflexion ROM, MVC, and a single‐limb balance test with eyes closed. The same three measurements were repeated after 10 minutes (min) of rest and prior to the interventions. Following the pre‐test, participants randomly performed either SS or SM for 3 sets of 30 seconds (s) with 10s of rest between each set. At one and 10 min post‐interventions the participants repeated the three measurements, for a third and fourth cycle of testing.

Results:

Roller massage increased and SS decreased maximal force output during the post‐test measurements, with a significant difference occurring between the two interventions at 10 min post‐test (p < 0.05, ES = 1.23, 8.2% difference). Both roller massage (p < 0.05, ES = 0.26, ~4%) and SS (p < 0.05, ES = 0.27, ~5.2%) increased ROM immediately and 10 min after the interventions. No significant effects were found for balance or EMG measures.

Conclusions:

Both interventions improved ankle ROM, but only the self‐massage with a roller massager led to small improvements in MVC force relative to SS at 10 min post‐intervention. These results highlight the effectiveness of a roller massager relative to SS. These results could affect the type of warm‐up prior to activities that depend on high force and sufficient ankle ROM.

Level of Evidence:

2c     

Spinal accessory nerve neuropathy following neck dissection

The most common complication of neck dissection is shoulder dysfunction due to manipulation of spinal accessory nerve, resulting in trapezius muscle atrophy mainly in procedures involving the posterior neck triangle.AimThis study used electromyography to evaluate the injury to the spinal accessory nerve following neck dissection.Materials and methodsProspective case series of 51 patients submitted to 60 neck dissections followed by physical therapy evaluation of shoulder dysfunction. Nerve integrity was evaluated before and after the surgery by means of surface EMG registering the electric activity of the trapezius muscle during voluntary contraction. The patients were grouped according to the type of neck dissection, presence of shoulder pain, impairment during abduction movement and hypotrophy/ atrophy of the trapezius muscle.ResultsAction potential had median values of 54.3 microV before surgery and 11.6 microV after it (p<0.001). There was a mean decrease of 70% comparing to preoperative values. The median was 12.5 microV after dissection including level IIb, and 8.9 microV after dissection including levels IIb and V (p<0.002).ConclusionSurface EMG is a sensitive and painless method for spinal accessory nerve dysfunction evaluation. The results suggest the usefulness of the trapezius muscle electromyography to confirm diagnosis and early physical therapy intervention in neuropathies of the spinal accessory nerve.     

局部肌肉疲劳主客观指标的相关性分析

目的探讨汽车装配工人动态作业局部肌肉疲劳时的表面肌电特征,通过主观疲劳指标与客观肌电指标的关联性分析,初步探讨评定局部肌肉疲劳的客观敏感指标与方法。方法选择水箱组装作业人员作为受试者;采用Biovision表面肌电仪采集受试者进行正常装配活动时右腕屈肌、右肱二头肌、右中三角肌、左/右斜方肌的表面肌电信号130 min;在肌电测试的同时,采用Borg'RPE量表每隔10 min询问一次受试者主观疲劳感受。以作业活动周期和参考动作(成品组件搬运)为单位,对肌电指标的变化情况及其与主观指标(RPE)之间的关系进行统计分析。结果肱二头肌、三角肌、右斜方肌的肌电最大随意收缩百分比(MVE%)值和中位频率(MF)值,左斜方肌的MF值与装配周期在统计学上存在明显负相关,但左斜方肌MVE%值、前臂腕屈肌MVE%值和MF值与装配周期无统计学相关。在自感疲劳出现时,各部位肌肉群的MVE%值均呈下降趋势,在疲劳持续发展期,该值下降缓慢或无明显变化;MF值在自感疲劳出现时呈明显下降趋势,在自感疲劳发生及持续发展期,该值下降缓慢或无明显变化。结论表面肌电信号改变与主观疲劳感两者之间具有一定的相关性,其早于主观自感疲劳的出现,提示表面肌电信号的改变可以用作机体早期疲劳的客观指标。     

肌电生物反馈对肝豆状核变性患者下肢肌张力障碍的影响

目的观察肌电生物反馈对肝豆状核变性患者下肢肌张力障碍的疗效。方法 40例肝豆状核变性并发肌张力障碍患者分为治疗组和对照组,每组20例。所有患者均接受正规驱铜治疗、改善肌张力药物治疗及针刺治疗。治疗组在此基础上对双下肢进行肌电触发生物反馈治疗。治疗前后用改良Ashworth量表及改良Barthel指数对患者进行评定,并测量踝背屈主动关节活动度变化。结果治疗后,两组患者的观察指标均有不同程度改善(P<0.05),治疗组疗效优于对照组(P<0.05)。结论肌电生物反馈能够改善肝豆状核变性患者下肢肌张力障碍,提高患者日常生活能力。     

冻结肩三维运动表面肌电信号特征分析

目的 通过肩周肌肉手法治疗前、后积分肌电值差异,探讨肩周肌肉功能变化。方法选取冻结肩患者7例,利用AMT-8肌电仪对手法治疗前、后肌肉肌电值进行采集,将数据用MATLAB软件进行分析,求积分肌电值。用Stata11.0软件统计。结果①外展时三角肌、冈下肌治疗前、后积分肌电值差异有统计学意义(P＜0.05),肱二头肌、肱...     

Distribution of affected muscles and degree of neurogenic lesion in patients with spina bifida

Introduction

Patients with spina bifida in the lumbosacral region usually have various degrees of motor and sensory dysfunctions of the lower extremities and anal sphincter. The aim of our study was to evaluate the distribution and differences in frequencies of affected muscles, number of affected muscles and degree of neurogenic lesion between patients with spina bifida occulta (SBO) and spina bifida aperta (SBA).

Material and methods

In 100 patients with SB, 6 muscles in the lower limbs were separately analysed. Due to the number of affected muscles, we evaluated 5 groups of patients: with 1 affected muscle, 2 affected muscles, 3 affected muscles, 4 affected muscles and 5 affected muscles. Three degrees of neurogenic lesions were assessed: mild, moderate and severe.

Results

The tibialis anterior muscle was most frequently affected in SB patients. The outer anal sphincter was frequently affected in the group of SBA patients. Single muscle affection is frequent in the group of patients with SBO, while in the group of patients with SBA, 4 muscles were significantly frequently affected. The great majority of patients (45.46%) with affected outer anal sphincter (OAS) in the group of SBO were without affection of other muscles, while for the SBA group it was for every third patient. Mild neurogenic lesion was significantly frequent in SBO patients, while severe form was significantly frequent in SBA patients.

Conclusions

Patients with SBO usually present with mild to moderate clinical presentation, while multiple root involvement and severe degree of neurogenic lesion is associated more frequently with SBA.     

Effects of different stimulus locations on inhibitory responses in human jaw-closing muscles

The aim of this study was to examine the inhibitory responses in bilateral masseter and temporalis muscle activity when electrical stimulation with short or long duration was applied to six oro-facial locations. The exteroceptive suppression period (ES2) and inhibitory responses were recorded in the surface electromyogram (EMG) of bilateral masseter and temporalis muscles in 16 healthy subjects. Two stimulus durations (1 ms single pulse and 450 ms pulse train) adjusted to a perceived intensity of 7 (distinct painful) on a 0-10 Numerical Rating Scale (NRS) were applied to the following six oro-facial locations on the right side while the subject was biting at 50% of the maximal voluntary contraction: masseter muscle, temporalis muscle, temporomandibular joint, infraorbital nerve, supraorbital nerve, and mental nerve. The stimulus intensity required to reach an NRS score of 7 was significantly lower for 450 ms train stimuli than for 1 ms single stimuli (P<0·001). There were no significant differences in the magnitude of ES2 suppression among the six different locations (P>0·876) for the 1 ms single stimuli. There were significant decreases in Root-Mean-Square-EMG values in the 400-500 ms post-stimulus epoch compared with the pre-stimulus epoch (P<0·023) for 450 ms train stimuli, but there were no significant differences in the magnitude of inhibition among the six different locations (P<0·893). Short- and long-lasting electrical stimulation of various oro-facial locations induces similar bilateral inhibitory effects in the jaw-closing muscles but with different propensity which may reflect the somatotopic organisation of these responses.