32 research outputs found
Modulation of spinal excitability following neuromuscular electrical stimulation superimposed to voluntary contraction
Purpose. Neuromuscular electrical stimulation (NMES) superimposed on voluntary muscle contraction has been recently
shown as an innovative training modality within sport and rehabilitation, but its effects on the neuromuscular system are
still unclear. The aim of this study was to investigate acute responses in spinal excitability, as measured by the Hoffmann
(H) reflex, and in maximal voluntary contraction (MVIC) following NMES superimposed to voluntary isometric
contractions (NMES+ISO) compared to passive NMES only and to voluntary isometric contractions only (ISO). Method.
Fifteen young adults were required to maintain an ankle plantar-flexor torque of 20% MVC for 20 repetitions during each
experimental condition (NMES+ISO, NMES and ISO). Surface electromyography was used to record peak-to-peak Hreflex and motor waves following percutaneous stimulation of the posterior tibial nerve in the dominant limb. An
isokinetic dynamometer was used to assess maximal voluntary contraction output of the ankle plantar flexor muscles.
Results. H-reflex amplitude was increased by 4.5% after the NMES+ISO condition (p < 0.05), while passive NMES and
ISO conditions showed a decrease by 7.8% (p < 0.05) and no change in reflex responses, respectively. There was no
change in amplitude of maximal motor wave and in MVIC torque during each experimental condition. Conclusion. The
reported facilitation of spinal excitability following NMES+ISO could be due to a combination of greater motor neuronal
and corticospinal excitability, thus suggesting that NMES superimposed onto isometric voluntary contractions may
provide a more effective neuromuscular stimulus and, hence, training modality compared to NMES alone
Active Vision during Action Execution, Observation and Imagery: Evidence for Shared Motor Representations
The concept of shared motor representations between action execution and various covert conditions has been demonstrated through a number of psychophysiological modalities over the past two decades. Rarely, however, have
researchers considered the congruence of physical, imaginary and observed movement markers in a single paradigm and never in a design where eye movement metrics are the markers. In this study, participants were required to perform a forward reach and point Fitts’ Task on a digitizing tablet whilst wearing an eye movement system. Gaze metrics were used to compare behaviour congruence between action execution, action observation, and guided and unguided movement imagery conditions. The data showed that participants attended the same task-related visual cues between conditions but the strategy was different. Specifically, the number of fixations was significantly different between action execution and all covert conditions. In addition, fixation duration was congruent between action execution and action observation only, and
both conditions displayed an indirect Fitts’ Law effect. We therefore extend the understanding of the common motor representation by demonstrating, for the first time, common spatial eye movement metrics across simulation conditions
and some specific temporal congruence for action execution and action observation. Our findings suggest that action
observation may be an effective technique in supporting motor processes. The use of video as an adjunct to physical
techniques may be beneficial in supporting motor planning in both performance and clinical rehabilitation environments
Fructose ingestion impairs expression of genes involved in skeletal muscle’s adaptive response to aerobic exercise
FISTULATION PERMANENTE DU PANCRÉAS EXOCRINE CHEZ LE PORC APPLICATION : RÉPONSE DE LA SÉCRÉTION PANCRÉATIQUE AU REPAS
International audienc
EFFET DU TRAITEMENT THERMIQUE DU TOURTEAU DE SOJA SUR LA VARIATION DE L'ÉQUIPEMENT ENZYMATIQUE DU PANCRÉAS EXOCRINE ET LES PERFORMANCES PONDÉRALES DU RAT APRÈS SEVRAGE
International audienc