Fine Wire EMG

INTRODUCTION: When an isometric contraction is sustained at a submaximal torque, activation of the motoneuron pool increases, making it difficult to measure neural excitability alterations. Thus, more recently, isometric contractions with maintained electromyographic activity (matched-EMG) are being used to induce fatigue; however, little is known about the neurophysiological adjustments that occur to satisfy the requirements of the task. METHODS: For our study, 16 participants performed a 10-min sustained isometric elbow flexion contraction at 20% maximal voluntary contraction (MVC) torque or the level of integrated biceps brachii EMG recorded at 20% MVC torque...

BACKGROUND: A strong body of literature has been published outlining muscle activity differences during sports performance in groups of overhead athletes. However, there are limited studies that have directly compared the muscle activity in overhead athletes with and without history of shoulder injury during functional everyday tasks. PURPOSE: This study aimed to identify muscle activities across fourteen upper extremity and core muscles during three functional everyday movements in athletes with and without history of shoulder injury...

INTRODUCTION: Core stability is crucial for preventing and rehabilitating lumbar spine injuries. An external focus instruction using a paper balloon is an effective way to activate the trunk muscles. However, the degree of trunk and lower extremity muscle activation during single leg stance with external focus instruction using a paper balloon is unknown. This study aimed to investigate the core muscle involving activity in the trunk and lower extremities on both the support and non-support sides with or without using external focus instruction using a paper balloon during isometric single-leg stance...

BACKGROUND: Vibration of one limb affects motor performance of the contralateral limb, and this may have clinical implications for people with lateralized motor impairments through vibration-induced increase in cortical activation, descending neural drive, or spinal excitability. OBJECTIVE: The objective of this study was to evaluate the effects of acute biceps brachii tendon vibration on force steadiness and motor unit activity in the contralateral limb of persons with Parkinson's disease...

Foot posture describes the anatomical variance in an individual's overall foot shape, an important consideration in the provision of foot orthoses. Current orthoses designs could be optimized by considering the topographical organization of cutaneous mechanoreceptors. Currently, the effect of foot orthoses designs to enhance skin stimulation across different anatomical foot posture remains unknown. Thus, the purpose of this study was to investigate how foot posture variance modulates lower leg muscle activity when walking in non-textured orthoses and in textured orthoses which facilitates cutaneous mechanoreceptors under five different regions of the foot sole...

Opioids are well-known to cause respiratory depression, but despite clinical evidence of dysphagia, effects of opioids on swallow excitability and motor pattern are unknown. We tested the effects of the clinically-relevant opioid buprenorphine on pharyngeal swallow and respiratory drive in male and female rats. We also evaluated the utility of 5-HT1A agonists (8-OH-DPAT and buspirone) to improve swallowing and breathing following buprenorphine administration. Experiments were performed on 44 freely breathing Sprague Dawley rats anesthetized with sodium pentobarbital...

The spatial distribution of muscle fibre activity is of interest in guiding therapy and assessing recovery of motor function following injuries of the peripheral or central nervous system. This paper presents a new method for stable estimation of motor unit territory centres from high-density surface electromyography (HDsEMG). This completely automatic process applies principal component compression and a rotatable Gaussian surface fit to motor unit action potential (MUAP) distributions to map the spatial distribution of motor unit activity...

Electromyography, commonly known as EMG, utilizes superficial or needle electrodes to record and analyze the fundamental electrical characteristics of skeletal muscles, determining whether the muscles are contracting. The motor unit, which consists of a collection of group muscle fibers and the motor neurons that govern them, is the structural basis of EMG. Three types of electrode are used in EMG which are needle electrode, fine wire electrode, and surface electrode. A significant amount of literature indicates that the correction of muscle function affects the relationships between teeth within the same jaw and between the jaws on opposing sides...

Foot orthoses (FO) are a commonly prescribed intervention to alter foot function during walking although their effects have been primarily studied in the extrinsic muscles of the foot. Furthermore, enhancing sensory feedback under the foot sole has been recently shown to alter extrinsic muscle activity during gait; however, the effects of FOs with enhanced sensory feedback on plantar intrinsic foot muscles (PIFMs) remain unknown. Thus, the purpose of this study was to investigate the effect of FOs with and without sensory facilitation on PIFM activity during locomotion...

Resistance training with low loads in combination with blood flow restriction (BFR) facilitates increases in muscle size and strength comparable with high-intensity exercise. We investigated the effects of BFR on single motor unit discharge behavior throughout a sustained low-intensity isometric contraction. Ten healthy individuals attended two experimental sessions: one with, the other without, BFR. Motor unit discharge rates from the tibialis anterior (TA) were recorded with intramuscular fine-wire electrodes throughout the duration of a sustained fatigue task...

Dynamic changes in jaw movements and bite forces depend on muscle architectural and neural factors that have rarely been compared within the same muscle. Here we investigate how regional muscle architecture dynamics-fascicle rotation, shortening, lengthening and architectural gear ratio (AGR)-vary during chewing across a functionally heterogeneous muscle. We evaluate whether timing in architecture dynamics relates to gape, food material properties and/or muscle activation. We also examine whether static estimates of temporalis fibre architecture track variation in dynamic architecture...

PURPOSE: This study aimed to evaluate the morphology of the three parts of the infraspinatus muscle based on surface landmarks for precise and effective access, and to propose the most effective fine-wire electrode insertion technique and sites. METHODS: Fifteen Asian fresh cadavers were used. We investigated the probability of the presence of the superior, middle, and inferior parts in each infraspinatus muscle based on surface landmarks. Based on the positional characteristics of the muscle, we determined the needle insertion method and confirmed its effectiveness by dissection...

Opioids are well-known to cause respiratory depression, but despite clinical evidence of dysphagia, the effects of opioids on swallow excitability and motor pattern are unknown. We sought to test the effects of the clinically-relevant opioid buprenorphine on pharyngeal swallow and respiratory drive in male and female rats. We also evaluated utility of serotonin 5-HT1A agonists (8-OH-DPAT and buspirone) to improve swallowing and breathing outcomes following buprenorphine administration. Experiments were performed on 44 freely breathing Sprague Dawley rats anesthetized with sodium pentobarbital...

BACKGROUND: Activity of specific neck muscles is modulated by eye movement. This activity modulation is exaggerated in people with whiplash associated disorders (WAD), but it is unknown whether it is impacted by sitting posture. OBJECTIVE: This study investigated; (i) whether activity of cervical muscles differs with spinal posture; (ii) whether the effect of eye gaze direction (horizontal/vertical) on neck muscle activity differs between postures, and (iii) whether these effects differ between individuals with and without WAD...

Despite the perceived importance of antagonist muscle activity, it is unknown if motor unit (MU) behaviour at recruitment differs when a muscle acts as an antagonist versus agonist. Fourteen healthy participants performed ramped, isometric elbow flexor and extensor contractions to 50 or 100% maximal voluntary contraction (MVC) torque. Surface and fine-wire intramuscular electromyographic (EMG) recordings were sampled from biceps and triceps brachii. During agonist contractions, low-threshold MUs (recruitment threshold <10% MVC torque) were sampled in all participants, with a total of 107 and 90 for biceps and triceps brachii, respectively...

Valid approaches for interfacing with and deciphering neural commands related to movement are critical to understanding muscular coordination and developing viable prostheses and wearable robotics. While electromyography (EMG) has been an established approach for mapping neural input to mechanical output, there is a lack of adaptability to dynamic environments due to a lack of data from dynamic movements. This report presents data consisting of simultaneously recorded high density surface EMG, intramuscular EMG, and joint dynamics from the tibialis anterior during static and dynamic muscle contractions...

The intrinsic and extrinsic muscles are considered to stabilize the foot and contribute to propulsion during walking. This study aimed to clarify the functional relationship between intrinsic and extrinsic muscles during walking. Thirteen healthy men participated in this study. The muscle activities of the intrinsic muscles (quadratus plantae and abductor hallucis), and the extrinsic muscles (flexor hallucis longus, flexor digitorum longus, and tibialis posterior) were measured using fine-wire and surface electromyography during walking...

INTRODUCTION: Excessive hip adduction and internal rotation are common movement impairments associated with patellofemoral pain (PFP). As such, strengthening of the hip abductors and external rotators commonly is recommended. Because tensor fascia latae (TFL) is a hip internal rotator in addition to being an abductor, it is important to select exercises that target the superior gluteus maximus (SUP-GMAX) and gluteus medius (GMED) while minimizing activation of the TFL. OBJECTIVE: To identify hip-targeted exercises resulting in greater activation of the SUP-GMAX and GMED relative to the TFL in persons with PFP...

This study explored effects of using isometric versus isokinetic maximal voluntary contractions (MVCs) to normalize EMG data from supraspinatus and infraspinatus subregions during isokinetic tasks. Participants performed submaximal isokinetic external rotation (ER) and scaption tasks at two speeds. Three isometric MVCs were used: seated ER; side-lying scaption; side-lying abduction. Isokinetic MVCs were performed in the same position and speeds as the experimental tasks. Data were normalized using peak EMG from reference tasks: MVC which produced the greatest amplitude overall (MEA), isometric MVC with greatest amplitude (isometric best), isokinetic MVC with greatest amplitude (isokinetic best), and the greatest amplitude from the isokinetic MVC that matched the experimental task (isokinetic matched)...

BACKGROUND: Clinical use of botulinum neurotoxins (BoNTs) in masticatory muscles is usually bilateral, but most studies on the functional consequences of BoNT treatment have used unilaterally treated animals. OBJECTIVES: To test the hypothesis that bilateral BoNT treatment of the rabbit masseter hampers mastication and to assess its effects on bone density of the mandibular condyles. METHODS: Ten 5-month-old female rabbits received injections of BoNT into both masseter muscles, and nine sham animals received saline...