Respiration monitoring by combining EMG and bioimpedance measurements

Full abstract in the manuscript

Repeated exercise stress impairs volitional but not magnetically evoked electromechanical delay of the knee flexors

The effects of serial episodes of fatigue and recovery on volitional and magnetically evoked neuromuscular performance of the knee flexors were assessed in twenty female soccer players during: (i) an intervention comprising 4x35s maximal static exercise; (ii) a control condition. Volitional peak force (PFV) was impaired progressively (-16 % vs. baseline: 235.3±54.7 to 198.1±38.5 N) by the fatiguing exercise and recovered to within -97 % of baseline values following six-minutes of rest. Evoked peak twitch force (PTFE) was diminished subsequent to the fourth episode of exercise (23.3 %: 21.4±13.8 vs. 16.4±14.6 N) and remained impaired at this level throughout the recovery. Impairment of volitional electromechanical delay performance (EMDV) following the first episode of exercise (25.5 % :55.3±11.9 vs. 69.5±24.5 ms) contrasted with concurrent improvement (10.0 %: 24.5±4.7 vs. 22.1±5.0 ms) in evoked electromechanical delay (EMDE) (p <0.05) and this increased disparity between EMDE and EMDV remained during subsequent periods of intervention and recovery. The fatiguing exercise provoked substantial impairments to volitional strength and EMDV that showed differential patterns of recovery. However, improved EMDE performance might identify a dormant capability for optimal muscle responses during acute stressful exercise and an improved capacity to maintain dynamic joint stabilty during critical episodes of loading

Quantitative hierarchical representation and comparison of hand grasps from electromyography and kinematic data

Motivation: Modeling human grasping and hand movements is important for robotics, prosthetics and rehabilitation. Several qualitative taxonomies of hand grasps have been proposed in scientific literature. However it is not clear how well they correspond to subjects movements. Objective: In this work we quantitatively analyze the similarity between hand movements in 40 subjects using different features. Methods: Publicly available data from 40 healthy subjects were used for this study. The data include electromyography and kinematic data recorded while the subjects perform 20 hand grasps. The kinematic and myoelectric signal was windowed and several signal features were extracted. Then, for each subject, a set of hierarchical trees was computed for the hand grasps. The obtained results were compared in order to evaluate differences between features and different subjects. Results: The comparison of the signal feature taxonomies revealed a relation among the same subject. The comparison of the subject taxonomies highlighted also a similarity shared between subjects except for rare cases. Conclusions: The results suggest that quantitative hierarchical representations of hand movements can be performed with the proposed approach and the results from different subjects and features can be compared. The presented approach suggests a way to perform a systematic analysis of hand movements and to create a quantitative taxonomy of hand movements

An Investigation Into the Electrical Activity of Tender, Resting Paraspinal Muscles Using Surface Electromyography: A Pilot Study

Abnormal resting paraspinal muscle activity has been claimed to be responsible for changes in spinal tissue texture which are detectible by manual palpation. This pilot study investigated whether there was significant electrical activity in paraspinal musculature that was tender and that appeared to have altered tissue texture on palpation. Sixteen healthy volunteers between 18 and 35 years of age had their thoracic erector spinae mass palpated bilaterally from spinal levels T3 to T10 to identify paraspinal regions exhibiting altered tissue texture relative to the contralateral muscle mass. Surface electromyography (sEMG) was used to measure electrical activity in the muscle mass at the selected levels. No significant differences in electrical activity were observed between the tender and non-tender muscle masses, although a large difference existed in the one symptomatic subject. All muscle sites displayed EMG activity at rest, although the source of activity is not clear. A number of methodological problems with the EMG recording were encountered and are discussed. Future research is recommended using symptomatic participants