Vertebral Displacements and Muscle Activity During Manual Therapy: Distinct Behaviors Between Spinal Manipulation and Mobilization

Objective

The purpose of this study was to compare vertebral displacements (absolute and relative) and muscle responses induced by spinal manipulative therapy of short (spinal manipulation) and long (spinal mobilization) impulse duration.

Immediate Effect of Acupuncture on Electromyographic Activity of the Upper Trapezius Muscle and Pain in Patients With Nonspecific Neck Pain: A Randomized,Single-Blinded,Sham-Controlled,Crossover Study

Objective

The objective of this study was to assess changes in upper trapezius myoelectric activity and pain in patients with nonspecific neck pain after a single session of acupuncture (ACP).

Electromyographic activity of posterior kinetic chain muscles during hamstring strengthening exercises

ObjectivesTo compare the muscle activation of the biceps femoris (BF), semitendinosus (ST), gluteus maximus (GM), and contralateral erector spinae (ES) in four specific eccentric hamstring-oriented exercises using overground maximal sprints as an EMG normalization method.Designcross-sectional study.Participantstwenty-four healthy athletes participated in this study.Main outcome measuresThe maximum EMG activation of all targeted muscles was measured during maximal sprints and four hamstring exercises: Nordic hamstring (NH), Russian belt (RB), glider (GL) and lying kick (LK). Maximum EMG activation during sprints were used to normalize EMG muscle activation.ResultsRB and GL showed lower hamstrings activation (from 15.71% to 39.23% and from 26.34% to 31.23%, respectively), so these exercises may be used as the first step of the retraining. The higher hamstring activation was reached in the NH (from 20.15% to 66.81%) and the LK (from 50.5% to 61.2%). Regarding muscles comparison, BF and ST were the most dependent on the exercise ranging from 26.67% to 62.22%, and from 26.34% to 66.81%, respectively.ConclusionsMuscle activation is dependent on the exercise procedure. RB and GL should be used as a first step because of their low activation. Instead, NH and LK should be used at the last phases of retraining process. Considering the synergistic activation of the PKC muscles during LK, and because of its unilateral and explosive characteristics, LK seems a suitable exercise for retraining PKC muscles in general.     

结肠通过时间和盆底肌电图检查对功能性便秘分型的临床意义

功能性便秘是一种常见的胃肠道功能性疾病，随着社会生活方式和饮食结构等的改变，其发病率正逐年增高，并向年轻化发展。正确的分型对该病治疗方法的选择具有指导意义。目的：探讨结肠通过时间和盆底肌电图检查对功能性便秘分型的临床意义。方法：选择符合功能性便秘罗马Ⅱ诊断标准的患者32例，病史6个月-30年不等。应用不透X线的标志物进行结肠通过时间检查，计算传输指数(TI)和结肠排出率；同时结合盆底肌电图检查观察是否存在盆底肌与腹部肌群的矛盾运动。结果：结肠通过时间检查显示20例患者为出口梗阻型便秘，12例为慢传输型便秘。盆底肌电图检查显示出口梗阻型便秘患者均存在不同程度的盆底肌与腹部肌群的矛盾运动，慢传输型便秘患者中有4例存在盆底肌与腹部肌群的矛盾运动。结论：采用结肠通过时间和盆底肌电图检查可对功能性便秘作出分型，方法简便易行且无痛苦。     

脑卒中后肩关节半脱位对偏瘫侧上肢周围神经电生理特征的影响

目的探讨脑卒中后肩关节半脱位对偏瘫侧上肢周围神经电生理参数的影响。方法纳入20例脑卒中伴肩关节半脱位的患者,分别对患者双上肢肩胛上神经、腋神经、肌皮神经、桡神经、正中神经、尺神经的运动神经传导及桡神经、正中神经、尺神经的感觉神经传导进行评估,并对偏瘫上肢冈上肌、三角肌、肱二头肌、伸指总肌、拇短展肌和小指展肌进行静息状态下针极肌电图检测;采用Brunnstrom分期对患者的上肢和手功能进行评估,并对患侧神经肌肉复合动作电位(CMAP)波幅的变化率与患者病程、年龄及上肢Brunnstrom分期进行相关性分析。结果与健侧相比,脑卒中后肩关节半脱位侧的肩胛上神经、腋神经、肌皮神经、桡神经、正中神经、尺神经CMAP波幅均显著降低(P<0.01),肩胛上神经和腋神经的潜伏期延长(P<0.05),肌皮神经、桡神经、正中神经和尺神经潜伏期双侧差异无统计学意义(P>0.05)。桡神经、正中神经和尺神经运动传导速度双侧无差异(P>0.05)。偏瘫侧腋神经、肩胛上神经、肌皮神经CMAP波幅变化率明显高于桡神经、正中神经和尺神经(P<0.05)。偏瘫侧桡神经、正中神经和尺神经的感觉神经动作电位(SNAP)较健侧降低(P<0.01),感觉传导速度双侧差异无统计学意义(P>0.05)。偏瘫侧SNAP波幅变化率由高到低依次为正中神经、桡神经和尺神经,但两两对比差异均无统计学意义(P>0.05),感觉神经传导速度变化率两两对比差异亦无统计学意义(P>0.05)。肩关节半脱位后上肢所检肌肉均存在不同程度的自发电位,偏瘫上肢近端出现率高于远端肢体,其中冈上肌自发电位出现率为61.54%,三角肌为84.62%,肱二头肌为69.23%,伸指总肌和拇短展肌为46.15%,小指展肌为30.77%。偏瘫侧CMAP变化率与患者病程、年龄及上肢Brunnstrom分期之间均无明显相关性(P>0.05)。结论脑卒中后肩关节半脱位可导致支配肩和上臂的周围神经损害程度大于支配前臂和手的神经,可能影响患者上肢功能的恢复。     

Flexed lumbar spine postures are associated with greater strength and efficiency than lordotic postures during a maximal lift in pain-free individuals

BackgroundInspite of common lifting advice to maintain a lordotic posture, there is debate regarding optimal lumbar spine posture during lifting. To date, the influence of lumbar posture on trunk muscle recruitment, strength and efficiency during high intensity lifting has not been fully explored.Research questionHow do differences in lumbar posture influence trunk extensor strength (moment), trunk muscle activity, and neuromuscular efficiency during maximal lifting?MethodsTwenty-six healthy participants adopted three lumbar postures (maximal extension (lordotic), mid-range (flat-back), and fully flexed) in a free lifting position. Motion analysis and force measurements were used to determine the back extensor, hip and knee moments. Surface electromyography (EMG) of three trunk extensors and the internal obliques were recorded. Neuromuscular efficiency (NME) was expressed as a ratio of normalised extensor moment to normalised EMG.ResultsSignificantly higher back extensor moments were exerted when moving from an extended to mid-range, and from a mid-range to fully flexed lumbar posture. This was accompanied by a decrease in activity across all three back extensor muscles (P < 0.001) resulting in a higher NME of these muscles in more flexed postures. Change in lumbar posture did not influence hip or knee moments or internal oblique activation.SignificanceA flexed-back posture is associated with increased strength and efficiency of the back muscles compared to a lordotic posture. These findings further question the manual handling advice to lift with a lordotic lumbar spine.     

The role of potassium in muscle membrane dysfunction in end-stage renal disease

ObjectiveUremic myopathy is a condition seen in end-stage renal disease (ESRD), characterized by muscle weakness and muscle fatigue, in which the pathophysiology is uncertain. The aim of this study was to assess the role of abnormal serum constituents in ESRD patients by relating them to the excitability properties of the tibialis anterior muscle, at rest and during electrically induced muscle activation, by recording muscle velocity recovery cycles (MVRC) and frequency ramp responses.MethodsEighteen ESRD patients undergoing hemodialysis were evaluated by blood sample, MVRC, and frequency ramp (before and near the end of dialysis treatment), quantitative electromyography, and nerve conduction studies. Patients were compared to 24 control subjects.ResultsIn patients, muscle relative refractory period, early supernormality, late supernormality after 5 conditioning stimuli, and latency of the last of 15 and 30 frequency ramp pulses were strongly associated with potassium levels (p < 0.01), showing depolarization before and normalization in the end of hemodialysis.ConclusionsIn ESRD patients, the muscle membrane is depolarized, mainly due to hyperkalemia.SignificanceSince normal muscle fatigue has been attributed to potassium-induced depolarization, it seems likely that this mechanism is also a major cause of the exaggerated muscle fatigue and weakness in ESRD patients.     

Abdominal bracing changes lower quarter muscle activity but not reach distances during active forward reach on an unstable surface

ObjectiveThis study examined the effects of abdominal bracing maneuver (ABM) performance on stable and unstable surfaces on active forward reach (AFR) distance as a measure of trunk control, measuring changes in reach distance and muscle activation patterns.DesignSingle-group, repeated measures design.MethodsTwenty-eight subjects (mean age 25 ± 5.09 years) performed an AFR with and without ABM while on stable and unstable surfaces. Lower quarter muscle activity and forward reach distances were recorded.ResultsForward reach distances on the unstable surface were significantly decreased compared to the stable condition with and without ABM (p < .001). The surface-by-contraction interaction was significant for the tibialis anterior (TA) and gastrocnemius (GS). Significant main effects were found for internal oblique, external oblique, gluteus maximus, biceps femoris, TA, and GS, where muscle activity significantly increased during the ABM trials. The interaction between surface and contraction was significant for the TA and GS muscles. TA (p = .007) and GS (p < .001) activity increased with ABM on the unstable surface. TA activity increased with ABM on the stable surface (TA: p < .001).ConclusionReach distances decreased on the unstable surface, but ABM did not change reaching distance. Ankle muscle co-contraction occurred during ABM trials and posterior chain activity increased. These changes suggest ABM may be beneficial during forward reaching activities.     

Control strategies for active lower extremity prosthetics and orthotics: a review

Technological advancements have led to the development of numerous wearable robotic devices for the physical assistance and restoration of human locomotion. While many challenges remain with respect to the mechanical design of such devices, it is at least equally challenging and important to develop strategies to control them in concert with the intentions of the user.This work reviews the state-of-the-art techniques for controlling portable active lower limb prosthetic and orthotic (P/O) devices in the context of locomotive activities of daily living (ADL), and considers how these can be interfaced with the user’s sensory-motor control system. This review underscores the practical challenges and opportunities associated with P/O control, which can be used to accelerate future developments in this field. Furthermore, this work provides a classification scheme for the comparison of the various control strategies.As a novel contribution, a general framework for the control of portable gait-assistance devices is proposed. This framework accounts for the physical and informatic interactions between the controller, the user, the environment, and the mechanical device itself. Such a treatment of P/Os – not as independent devices, but as actors within an ecosystem – is suggested to be necessary to structure the next generation of intelligent and multifunctional controllers.Each element of the proposed framework is discussed with respect to the role that it plays in the assistance of locomotion, along with how its states can be sensed as inputs to the controller. The reviewed controllers are shown to fit within different levels of a hierarchical scheme, which loosely resembles the structure and functionality of the nominal human central nervous system (CNS). Active and passive safety mechanisms are considered to be central aspects underlying all of P/O design and control, and are shown to be critical for regulatory approval of such devices for real-world use.The works discussed herein provide evidence that, while we are getting ever closer, significant challenges still exist for the development of controllers for portable powered P/O devices that can seamlessly integrate with the user’s neuromusculoskeletal system and are practical for use in locomotive ADL.