Showing papers in "Journal of Electromyography and Kinesiology in 2003"

TL;DR: Concerning the role of neuromuscular control system, increased body sway has been found in patients with low back pain, indicating a less efficient muscle control system with decreased ability to provide the needed spinal stability.

TL;DR: It is argued that, at least in some cases, pain may cause the changes in control of the trunk muscles in people with low back pain, and strategies of prevention and rehabilitation of LBP are argued.

TL;DR: It is proposed that motor control changes in patients are functional in that they enhance spinal stability and suggest an alternative model to explain the alterations of trunk muscle recruitment due to low-back pain.

TL;DR: The collection of works synthesized here point to the notion that stability results from highly coordinated muscle activation patterns involving many muscles, and that the recruitment patterns must continually change, depending on the task.

TL;DR: Computer simulations and experimental findings suggest that multiple mechanisms contribute to the differences in force fluctuations between young and old adults, although the boundary conditions for each mechanism remain to be determined.

TL;DR: It is demonstrated that theory does not predict a linear relation between the characteristic frequencies (maximum, mean and median) and MFPV, and the ability of muscle fibres to uptake Ca(2+) back into the sarcoplasmic reticulum could be the limiting site for fatigue.

TL;DR: Two non-linear model of the plantarflexor series elastic elements resulted in three closely validated predictions of anterior/posterior balance: the locus of the gravitational load line, the predicted ankle moment and the ankle stiffness at the operating point.

TL;DR: In this review, the basic principles of operation of linear electrode arrays for the detection of surface EMG signals are described, together with their most relevant current applications.

TL;DR: It was a finding of this study that four asymptomatic subjects did not pre-activate, therefore providing a rationale for future prospective investigations on whether the lack of TrA/IO feed-forward activation is a cause or an effect of low back pain.

TL;DR: It was concluded that the isokinetic MVC method should not be adopted by gait researchers or clinicians as it does not reduce intra- or inter-individual variability anymore than existing normalisation methods, nor does it provide a more representative measure of muscle activation during gait than the isometric M VC method.

TL;DR: The critically damped filter was shown to have superior performance in the time domain than the butterworth filter, but for data that need to be double differentiated (e.g. displacement data) the Butterworth filter may still be the better choice.

TL;DR: Results were a more pronounced increase in EMG RMS amplitude for the three muscles and in MPF for the VL muscle with force in men compared with women, and no significant effect of gender was found with regards to fatigue.

TL;DR: The co-contraction index (CI) can be useful when examining muscle co-activation using EMG measurements in drop jumps, however, the conclusions on muscleCo-activation depend on the equation used to estimate CI and therefore a commonly accepted method is necessary.

TL;DR: Results indicated a decrease in ground impact force and an increase in maximum joint flexion during landing with fatigue, and these changes may have been influenced by other factors, in addition to fatigue, such as a neuromuscular protective mechanism to decrease impact force magnitude.

TL;DR: It was concluded that sustained static or cyclic loading of lumbar viscoelastic tissues may cause micro-damage in the collagen structure, which in turn reflexively elicit spasms in the multifidus as well as hyperexcitability early in the recovery when the majority of the creep recovers.

TL;DR: The recruitment threshold may be lower in dynamic as compared to isometric actions, and the recruitment of fast motor units may continue to higher force levels in isometric and in concentric as in eccentric actions.

TL;DR: This study improved knowledge of crosstalk and electrode spacing issues, and further examination of forearm EMG is required to improve understanding of muscle loading, EMG properties and motor control during gripping tasks.

TL;DR: The findings suggest the IP method is robust with large variance in the baseline if the signal to noise ratio is greater than six, and statistical assessments should be used to target trials for selective visual inspection for subtle trunk muscle onsets.

TL;DR: Results indicate that inertial properties influence the lower extremity muscular activity in addition to the cadence effect.

TL;DR: In this article, the reliability of peak torque and surface electromyography (EMG) variable's root mean square (RMS) and mean frequency (MNF) during an endurance test consisting of repetitive maximum concentric knee extensions was investigated.

TL;DR: The surface EMG technique at the global level of amplitude and spectral analysis cannot be used to characterize fatigue properties of low back muscles during very low level, long duration contractions since in these cases the non-stable MU pool has a major influence on the EMG variables.

TL;DR: The EMG fatigue parameters did not detect differences between genders but unexpectedly, healthy men showed higher fatigability than back pain patients, and an attempt was made to predict maximal back strength from anthropometric measurements but this prediction was prone to errors.

TL;DR: Analytical findings emphasize that the spinal stiffness (as well as muscular stiffness) is important in maintaining spinal stability, and that the stiffness-increasing effect of 'preloading' should be taken into account in stability analyses.

TL;DR: It is concluded that long term fatigue after intermittent contractions at low force levels can be detected even after 30 min of recovery in a low force test contraction.

TL;DR: The Cinderella hypothesis, which postulates the continuous activity of specific motor units (MUs) during low-level muscle contraction, is supported in subjects exposed to long-term computer work.

TL;DR: It was concluded that abduction or abduction with the arms in lateral rotation should be used as normalization contraction positions for the upper trapezius muscle and Site 1 was found to produce the most reliable data.

TL;DR: The muscles of the lower extremities are capable of stabilizing the tibiotalar and the talonavicular joints actively, restricting their maximal motion by means of a higher activation before and after touchdown.

TL;DR: The EMG spectrum is unaffected by impedance provided skin preparation is sufficient to reduce the impedance below 55 komega, and when skin impedance is electrically modelled with a simple network containing a resistor and a capacitor, the capacitance varies with the properties of the electrode used, whereas resistance is dependent on the subject.

TL;DR: The findings suggest that MU recruitment strategies are significantly related to the speed of contraction even in a single muscle.

TL;DR: The results showed that there were significant gender specific differences, which allowed more than a 95% correct classification of the subjects as males or females, and classification was possible irrespective of the shod condition while running.