Showing papers by "Serge S. Colson published in 2014"
TL;DR: On a VV platform, the use of a high platform displacement in combination with a high vibration frequency to provoke the highest muscle activity enhancement is recommended.
Abstract: To describe the most effective parameters maximizing muscle activity during whole-body vibration (WBV) exercises on a vertically vibrating (VV) platform. The influence of (1) WBV vs. no vibration, (2) vibration frequency (25, 30, 35, 40 Hz), (3) platform peak-to-peak displacement (1.2, 2 mm), and (4) additional loading (no load, 17, 33 kg) on surface electromyographic (sEMG) activity of five lower limb muscles was investigated in eighteen participants. (1) Comparing WBV to no vibration, sEMGRMS of the calf muscles was significantly higher with an additional load of 33 kg independently of the displacement and the frequency (P < 0.05). During WBV, (2) muscle activity at 40 Hz WBV was significantly higher than at 25 Hz for the gastrocnemius lateralis (GL) for all loads, and for the vastii medialis and lateralis using the 33 kg load (P < 0.05); (3) sEMGRMS of all lower limb muscles was significantly increased with the 2 mm compared to the 1.2 mm peak-to-peak displacement (P < 0.05); (4) an effect of additional load was found in the GL, with significantly higher neuromuscular activation for the 33 kg load than no load (P < 0.05). On a VV platform, we recommend the use of a high platform displacement in combination with a high vibration frequency to provoke the highest muscle activity enhancement. Without maxing out the acceleration stimuli, calf muscles’ sEMG can be enhanced with an additional load of 33 kg which corresponded to 50 % of the body mass.
39 citations
TL;DR: Whether the current intensity was increased or not, the adaptations after a NMES protocol yield to similar muscle fatigue adaptations as voluntary contractions likely through similar pathways matching a similar TTI.
Abstract: This study was designed to investigate whether the intensity modulation of a neuromuscular electrical stimulation (NMES) protocol delivered over the nerve trunk of the plantar flexors would lead to differential peripheral and central contributions of muscle fatigue. Three fatiguing isometric protocols of the plantar flexors matched for the same amount of isometric torque-time integral (TTI) were randomly performed including a volitional protocol at 20 % of the maximal voluntary contraction (MVC) and two NMES protocols (one at constant intensity, CST; the other at intensity level progressively adjusted to maintain 20 % of MVC, PROG). No time x protocol interaction was found for any of the variables. The MVC decreased similarly (≈12 %, p < 0.001) after all protocols, so did the potentiated twitch responses (p = 0.001). Although voluntary activation of the plantar flexors did not change, maximal H-reflex to M-wave ratio of the soleus (SOL) and the gastrocnemius medialis (GM) muscles showed an overall increase (SOL: p = 0.037, GM: p = 0.041), while it remained stable for the gastrocnemius lateralis muscle (p = 0.221). A main time effect was observed only for the SOL maximal V-wave to the superimposed M-wave ratio (p = 0.024) and to the superimposed H-reflex (p = 0.008). While similar central and peripheral adaptations were observed after the three fatiguing protocols, the individual contribution of the three different triceps surae muscles was different. Whether the current intensity was increased or not, the adaptations after a NMES protocol yield to similar muscle fatigue adaptations as voluntary contractions likely through similar pathways matching a similar TTI.
13 citations
TL;DR: Findings indicate that beliefs about PA can be enhanced in old sedentary females through targeted PA intervention, thus providing support to a malleable conception of exercise stereotypes in older adults.
10 citations
TL;DR: In this article, the authors present les methodes de normalisation des signaux EMGs and leur influence on les relations EMGsangle and EMGs-vitesse angulaire des muscles agonistes and antagonistes.
Abstract: En sciences du mouvement humain, l’introduction et le developpement des dynamometres isocinetiques a permis de faciliter les mesures de moment musculaire produit lors de contractions isometrique, concentrique et excentrique au cours de mouvements mono-articulaires. Toutefois, le recueil concomitant de l’activite electrique des muscles agonistes et antagonistes impliques dans le mouvement par electromyographie de surface (EMGs) reste peu exploite. Bien que de nombreuses precautions methodologiques doivent etre prises lors du recueil et de l’interpretation des signaux EMGs, cette methode permet d’obtenir un indicateur de l’etat de la commande nerveuse tres interessant dans les domaines des sciences du sport, de l’ergonomie, de la medecine physique. Cet article presente les methodes de normalisation des signaux EMGs et leur influence sur les relations EMGs-angle et EMGs-vitesse angulaire des muscles agonistes et antagonistes a la production de moment musculaire.
2 citations