Whole body angular momentum characterizes reactive balance adaptations and perturbation intensity.

Identifying measures which accurately quantify reactive balance adaptation during walking is essential to understand how emerging perturbation-based gait paradigms impact stability over the course of an intervention. These perturbation paradigms have shown promise in reducing falls for numerous clinical populations, however tracking progress in objective terms throughout an intervention remains challenging. Whole body angular momentum (H) may be particularly suited to detect subtle adaptations in the reactive balance response and is applicable within numerous perturbation environments.

Immediate effect of local vibration on motor unit firing behavior and muscle strength in healthy young adult males.

Purpose: The aim of this study was to examine the effect of vibration on motor unit (MU) firing behavior and physical performance of antagonist muscles in healthy young adult males.

Methods: Fourteen males (age = 24.3 ± 3.

Influence of stimulation frequency on brain-derived neurotrophic factor and cathepsin-B production in healthy young adults.

Electrical muscle stimulation (EMS) has been shown to stimulate the production of myokines (i.e., brain-derived neurotrophic factor (BDNF)), but the most effective EMS parameters for myokine production have not been fully elucidated.

Altered Cortical Activity during a Finger Tap in People with Stroke.

This study describes electroencephalography (EEG) measurements during a simple finger movement in people with stroke to understand how temporal patterns of cortical activation and network connectivity align with prolonged muscle contraction at the end of a task. We investigated changes in the EEG temporal patterns in the beta band (13-26 Hz) of people with chronic stroke (N = 10, 7 F/3 M) and controls (N = 10, 7 F/3 M), during and after a cued movement of the index finger. We quantified the change in beta band EEG power relative to baseline as activation at each electrode and the change in task-based phase-locking value (tbPLV) and beta band task-based coherence (tbCoh) relative to baseline coherence as connectivity between EEG electrodes.

Noninvasive estimation of skeletal muscle oxygen consumption rate and microvascular reactivity in chronic stroke survivors using near-infrared spectroscopy.

Understanding post-stroke changes in skeletal muscle oxidative metabolism and microvascular reactivity could help create therapeutic targets that optimize rehabilitative interventions. Due to disuse atrophy, we hypothesized that basal muscle oxygen consumption rate and microvascular endothelial function would be impaired in the tibialis anterior (TA) muscle of the affected leg of chronic stroke survivors compared with the nonaffected leg and versus matched controls. Fifteen chronic stroke survivors (10 females) and 15 matched controls (9 females) completed this study.

People with degenerative cervical myelopathy have impaired reactive balance during walking.

Background: People with degenerative cervical myelopathy are known to have impaired standing balance and walking abilities, but less is known about balance responses during walking.

Research Question: The aim of this project was to assess reactive balance impairments during walking in people with degenerative cervical myelopathy (PwDCM). We hypothesized that center of mass motion following perturbations would be larger in PwDCM and gluteus medius electromyographic amplitude responses would be decreased in PwDCM.

Sex differences in laterality of motor unit firing behavior of the first dorsal interosseous muscle in strength-matched healthy young males and females.

Purpose: The purpose of this study was to compare laterality in motor unit firing behavior between females and males.

Methods: Twenty-seven subjects (14 females) were recruited for this study. The participants performed ramp up and hold isometric index finger abduction at 10, 30, and 60% of their maximum voluntary contraction (MVC).

Cortical effects of wrist tendon vibration during an arm tracking task in chronic stroke survivors: An EEG study.

The purpose of this study was to characterize changes in cortical activity and connectivity in stroke survivors when vibration is applied to the wrist flexor tendons during a visuomotor tracking task. Data were collected from 10 chronic stroke participants and 10 neurologically-intact controls while tracking a target through a figure-8 pattern in the horizontal plane. Electroencephalography (EEG) was used to measure cortical activity (beta band desynchronization) and connectivity (beta band task-based coherence) with movement kinematics and performance error also being recorded during the task.

Reduced oxygen desaturation in the vastus lateralis of chronic stroke survivors during graded muscle contractions.

Background: Few studies have examined changes in skeletal muscle physiology post-stroke. This study examined changes in tissue oxygen saturation (StO) of the vastus lateralis (VL) muscle of stroke survivors and age-matched control participants during maximal and submaximal isometric contractions of the knee extensor muscles.

Objectives: We hypothesized that tissue oxygen desaturation (ΔStO) during knee extensor muscle contractions would be less in the VL in the paretic vs.

Quantification of Tissue Oxygen Saturation in the Vastus Lateralis Muscle of Chronic Stroke Survivors during a Graded Exercise Test.

Purpose: This study examined tissue oxygen saturation (StO) of the vastus lateralis (VL) muscles of chronic stroke survivors during a graded exercise test (GXT). We hypothesized the reduction in StO will be blunted in the paretic vs. non-paretic VL during a maximum-effort GXT.

Influence of forward head posture on muscle activation pattern of the trapezius pars descendens muscle in young adults.

Forward head posture (FHP) is a serious problem causing head and neck disability, but the characteristics of muscle activity during long-term postural maintenance are unclear. This study aimed to investigate a comparison of electromyography (EMG) activation properties and subjective fatigue between young adults with and without habitual FHP. In this study, we examined the changes in the spatial and temporal distribution patterns of muscle activity using high-density surface EMG (HD-SEMG) in addition to mean frequency, a conventional measure of muscle fatigue.

Electrical muscle stimulation in young adults: effect of muscle volume on brain-derived neurotrophic factor levels.

Purpose: Electrical muscle stimulation (EMS) is known to be effective at stimulating brain-derived neurotrophic factor (BDNF) levels, but the relationship between the volume of muscle stimulated and BDNF levels is not clear. The purpose of this study was to quantify BDNF as a function of muscle volume stimulated in young adults.

Methods: Twelve young adults (male, n = 9, age = 27.

Changes in Cortical Activity in Stroke Survivors Undergoing Botulinum Neurotoxin Therapy for Treatment of Focal Spasticity.

Botulinum NeuroToxin-A (BoNT-A) relieves muscle spasticity and increases range of motion necessary for stroke rehabilitation. Determining the effects of BoNT-A therapy on brain neuroplasticity could help physicians customize its use and predict its outcome. The purpose of this study was to investigate the effects of Botulinum Toxin-A therapy for treatment of focal spasticity on brain activation and functional connectivity.

Detecting motor unit abnormalities in amyotrophic lateral sclerosis using high-density surface EMG.

Objective: The purpose of this study was to detect specific motor unit (MU) abnormalities in people with amyotrophic lateral sclerosis (ALS) compared to controls using high-density surface electromyography (HD-SEMG).

Methods: Sixteen people with ALS and 16 control subjects. The participants performed ramp up and sustained contractions at 30% of their maximal voluntary contraction.

Laterality of the activation of the vastus lateralis muscle in females with Parkinson's disease during the medication state compared with healthy controls.

The aim of this study was to quantify the laterality of motor unit (MU) activation properties in people with Parkinson's disease (PD) during force production (low- to high-intensity contraction) using high-density surface electromyography (HD-SEMG). Sixteen females with PD (age = 69.9 ± 7.

Association between the Degree of Pre-Synaptic Dopaminergic Pathway Degeneration and Motor Unit Firing Behavior in Parkinson's Disease Patients.

The relationship between motor unit (MU) firing behavior and the severity of neurodegeneration in Parkinson's disease (PD) is not clear. This study aimed to elucidate the association between degeneration with dopaminergic pathways and MU firing behavior in people with PD. Fourteen females with PD (age, 72.

Accelerometer Calibration: The Importance of Considering Functionality.

Purpose: To compare the accuracy and precision of a hip-worn accelerometer to predict energy cost during structured activities across motor performance and disease conditions.

Methods: 118 adults self-identifying as healthy ( = 44) and those with arthritis ( = 23), multiple sclerosis ( = 18), Parkinson's disease ( = 17), and stroke ( =18) underwent measures of motor performance and were categorized into groups: Group 1, usual; Group 2, moderate impairment; and Group 3, severe impairment. The participants completed structured activities while wearing an accelerometer and a portable metabolic measurement system.

Influence of hybrid assistive limb gait training on spatial muscle activation patterns in spinal muscular atrophy type III.

Despite the potential benefits, the effects of Hybrid Assistive Limb (HAL) gait training on changes in neuromuscular activation that accompany functional gains in individuals with spinal muscular atrophy (SMA) type III is not well known. In this article, we quantify the effects of HAL gait training on spatial muscle activity patterns in a patient with SMA type III using multi-channel surface electromyography (SEMG). A 21-years old male (168 cm, 47.

The Effect of Electrical Muscle Stimulation on Muscle Mass and Balance in Older Adults with Dementia.

Background: Electrical muscle stimulation (EMS) is effective for increasing physical function. However, there is no evidence regarding the effects of EMS on muscle mass and physical function in older adults with dementia. The aim of the present study was to quantify the effects of EMS on muscle mass and balance in older adults with dementia.

Electroencephalography resting-state networks in people with Stroke.

Introduction: The purpose of this study was to characterize resting-state cortical networks in chronic stroke survivors using electroencephalography (EEG).

Methods: Electroencephalography data were collected from 14 chronic stroke and 11 neurologically intact participants while they were in a relaxed, resting state. EEG power was normalized to reduce bias and used as an indicator of network activity.

Identification of Latent Classes of Motor Performance in a Heterogenous Population of Adults.

Objective: To determine classes of motor performance based on community deployable motor impairment and functional tests in a heterogeneous adult population.

Design: Sixteen tests of limb-specific and whole-body measures of motor impairment and function were obtained. Linear regression analysis was used to dichotomize performance on each test as falling within or outside the age- and sex-predicted values.

Improving gait efficiency to increase movement and physical activity - The impact of abnormal gait patterns and strategies to correct.

Increasing daily steps is important to maintain health and prevent both initial and subsequent cardiovascular (CV) disease (CVD) events. Even 5000 steps have been associated with reduced risk of CVD, however many adults and those with CVD walk fewer than 5000 daily steps. Reduced gait speed is a precursor to decreased physical engagement and is associated with biomarker changes linked to higher risk of CVD.

Impaired Firing Behavior of Individually Tracked Paretic Motor Units During Fatiguing Contractions of the Dorsiflexors and Functional Implications Post Stroke.

This study quantified stroke-related changes in the following: (1) the averaged discharge rate of motor units (individually tracked and untracked) identified from high-density electromyography (HD-EMG) recordings, (2) global muscle EMG properties of the dorsiflexors during a fatiguing contraction, and the relationship between task endurance and measures of leg function. Ten individuals with chronic stroke performed a sustained sub-maximal, isometric, fatiguing dorsiflexion contraction in paretic and non-paretic legs. Motor-unit firing behavior, task duration, maximal voluntary contraction strength (MVC), and clinical measures of leg function were obtained.