Torque Estimation Using Neural Drive for a Concentric Contraction.

The scope and relevance of wearable robotics spans across a number of research fields with a variety of applications. A challenge across these research areas is improving user-interface control. One established approach is using neural control interfaces derived from surface electromyography (sEMG).

motoRneuron: an open-source R toolbox for time-domain motor unit analyses.

Motor unit synchronization is the tendency of motor neurons and their associated muscle fibers to discharge near-simultaneously. It has been theorized as a control mechanism for force generation by common excitatory inputs to these motor neurons. Magnitude of synchronization is calculated from peaks in cross-correlation histograms between motor unit discharge trains.

Response Complexity Reduces Errors on a Response Inhibition Task.

Objective: The purpose of this investigation was to elucidate the role of button-response complexity to targets in a response inhibition task.

Background: Response inhibition is the ability to correctly inhibit an overt response to a target. The U.

The effect of imperceptible Gaussian tendon vibration on the Hoffmann reflex.

Imperceptible vibratory Gaussian noise stimulation to the periphery is frequently being applied to humans to enhance motor performance. It is commonly theorized that this stimulation creates a Stochastic Resonance-like effect across both sensory and motor systems, but this idea has no empirical support. In contrast, there is substantial work showing that tendon vibration can be both excitatory and inhibitory on the lower motor neuron output.

Differences in muscle contraction onset as determined by ultrasound and electromyography.

Introduction: We characterize the agreement between the timing of muscle contraction onset detected by surface electromyography (sEMG), fine wire EMG (fwEMG), and motion-mode (M-mode) ultrasound for improved interpretations of clinical outcomes.

Methods: Eighteen healthy adults participated. Differences in contraction onset were compared between sEMG, fwEMG, and M-mode ultrasound collected during concentric contractions of the vastus lateralis and biceps brachii.

Relationships Between Neuromuscular Function and Functional Balance Performance in Firefighters.

The purpose of the present study was to examine the relationships between neuromuscular function and functional balance performance in firefighters. Fifty career firefighters (35.1 ± 7.

The Influence of Habitual Protein Intake on Body Composition and Muscular Strength in Career Firefighters.

Objective: The aim of this research was to determine the relationship among protein (PRO) intake, body composition, and muscle strength in overweight and obese firefighters. A secondary objective was to evaluate differences in body composition and muscle strength among overweight and obese firefighters with low (L; < 0.8 g·kg), moderate (M; 0.

Consistency of a mobile body composition trailer: a novel portable laboratory assessment?

Objective: The purpose of this investigation was to (i) assess the test-retest reliability and minimum difference (MD) values of air-displacement plethysmography (ADP) and the Siri 3-compartment (3-C) model in a mobile trailer, and (ii) identify any environmental fluctuations in the trailer.

Methods: percent body fat (%BF) was examined in 22 firefighters on two separate days in a climate-controlled mobile trailer using ADP. Total body water was examined in a subset of participants (n = 12) using bioelectrical impedance spectroscopy (BIS) to determine %BF using Siri's 3-C model.

Iterative Assessment of Statistically-Oriented and Standard Algorithms for Determining Muscle Onset with Intramuscular Electromyography.

The onset of muscle activity, as measured by electromyography (EMG), is a commonly applied metric in biomechanics. Intramuscular EMG is often used to examine deep musculature and there are currently no studies examining the effectiveness of algorithms for intramuscular EMG onset. The present study examines standard surface EMG onset algorithms (linear envelope, Teager-Kaiser Energy Operator, and sample entropy) and novel algorithms (time series mean-variance analysis, sequential/batch processing with parametric and nonparametric methods, and Bayesian changepoint analysis).

Analysis of statistical and standard algorithms for detecting muscle onset with surface electromyography.

The timing of muscle activity is a commonly applied analytic method to understand how the nervous system controls movement. This study systematically evaluates six classes of standard and statistical algorithms to determine muscle onset in both experimental surface electromyography (EMG) and simulated EMG with a known onset time. Eighteen participants had EMG collected from the biceps brachii and vastus lateralis while performing a biceps curl or knee extension, respectively.

Computer-Based Algorithmic Determination of Muscle Movement Onset Using M-Mode Ultrasonography.

The study purpose was to evaluate the use of computer-automated algorithms as a replacement for subjective, visual determination of muscle contraction onset using M-mode ultrasonography. Biceps and quadriceps contraction images were analyzed visually and with three different classes of algorithms: pixel standard deviation (SD), high-pass filter and Teager Kaiser energy operator transformation. Algorithmic parameters and muscle onset threshold criteria were systematically varied within each class of algorithm.

The influence of subcutaneous fat on the relationship between body composition and ultrasound-derived muscle quality.

Ultrasound echo intensity (EI) values are a popular assessment of muscle quality. The relationship between EI and total (%fat) and regional (%fat) body composition was examined in 40 men, prior to and after accounting for subcutaneous fat thickness. Uncorrected EI values suggest that muscle quality improves (r = -0.

Cognitive Fatigue Influences Time-On-Task during Bodyweight Resistance Training Exercise.

Prior investigations have shown measurable performance impairments on continuous physical performance tasks when preceded by a cognitively fatiguing task. However, the effect of cognitive fatigue on bodyweight resistance training exercise task performance is unknown. In the current investigation 18 amateur athletes completed a full body exercise task preceded by either a cognitive fatiguing or control intervention.

The influence of ultrasound measurement techniques on the age-related differences in Achilles tendon size.

Achilles tendon (AT) properties change with age, however the extent to which aging influences the size of the AT may be influenced by the measurement technique. The purpose of this study was to 1) examine the age-related differences in AT size using measures of cross-sectional area (CSA) and thickness, and 2) to determine the test-retest reliability and minimum difference (MD) values of these measures. The size of the AT was examined in 19 young (19.

Influence of Lower Extremity Muscle Size and Quality on Stair-Climb Performance in Career Firefighters.

The purpose of this study was to examine the influence of lower extremity muscular size and quality on stair-climb performance (SCP) in career firefighters. Forty-six male career firefighters (age = 37.0 ± 7.

Pennation angle does not influence the age-related differences in echo intensity of the medial gastrocnemius.

The reflection of an ultrasound (US) wave is strongest when the propagation direction of the wave is perpendicular to muscle fascicles. Thus, it is possible that muscle echo intensity (EI), a gray-scale US measure of muscle quality, may be influenced by the angulation of muscle fascicles. Therefore, the purpose of this study was to determine if age-related differences in muscle EI values are influenced by differences in pennation angle (PA).

Changes in resting heart rate variability across the menstrual cycle.

Heart rate variability (HRV) is a noninvasive indicator of autonomic control. This study examines HRV changes across a normal menstrual cycle and proposes a novel piecewise function controlling for the effects of breathing on HRV spectral parameters. A resting ECG was collected from 13 women at five points in their menstrual cycle.