The current study examined the effects of using an unstable surface during whole-body vibration (WBV) exercise on leg and trunk muscle activity during a static semi-squat. Twenty-eight recreationally active university students completed 4 different test conditions: 1) stable surface with no WBV; 2) unstable surface with no WBV; 3) unstable surface with 30 Hz WBV low amplitude; and 4) unstable s...

BACKGROUND: Muscle fatigue can be defined as the failure of a muscle to maintain a reasonably expected force output. The multivariate approach to fatigue assessment is used because the multiple (EMG) feature provides more information than anyone. OBJECTIVE: This study presents a method of assessing muscle fatigue during endurance testing at 50% maximal voluntary contraction (MVC) using electro...

The study compared changes in intramuscular and surface recordings of EMG amplitude with ultrasound measures of muscle architecture of the elbow flexors during a submaximal isometric contraction. Ten subjects performed a fatiguing contraction to task failure at 20% of maximal voluntary contraction force. EMG activity was recorded in biceps brachii, brachialis, and brachioradialis muscles using ...

Rectification of surface EMG prior to spectral analysis is a well established pre-processing method used in the detection of motor unit firing patterns. A number of recent studies have called into question the need for rectification prior to spectral analysis, pointing out that there is no supporting experimental evidence to justify rectification. We present an analysis of 190 records from 13 s...

This brief review discusses the methods used to estimate the neural drive to muscles from the surface electromyogram (EMG). Surface EMG has been classically used to infer the neural activation of muscle by associating its amplitude with the number of action potentials discharged by a population of motor neurons. Although this approach is valuable in some applications, the amplitude of the surfa...

This report describes an early version of a technique for decomposing surface electromyographic (sEMG) signals into the constituent motor unit (MU) action potential trains. A surface sensor array is used to collect four channels of differentially amplified EMG signals. The decomposition is achieved by a set of algorithms that uses a specially developed knowledge-based Artificial Intelligence fr...

A surface EMG signal represents the linear transformation of motor neuron discharge times by the compound action potentials of the innervated muscle fibers and is often used as a source of information about neural activation of muscle. However, retrieving the embedded neural code from a surface EMG signal is extremely challenging. Most studies use indirect approaches in which selected features ...

The objective of this study is to re-evaluate the relation between surface electromyogram (EMG) and muscle contraction torque in biceps brachii (BB) muscles of healthy subjects using two different complexity measures. Ten healthy subjects were recruited and asked to complete a series of elbow flexion tasks following different isometric muscle contraction levels ranging from 10% to 80% of maximu...

Despite the many reviews and research papers on the limitations of surface electromyography (EMG), there are relatively few that address this issue by considering dynamic contractions and specifically from the point of view of muscle coordination. Nevertheless, whether muscle coordination can be precisely studied using surface EMG signals is still a matter of discussion in the scientific commun...