Électromyostimulation et récupération fonctionnelle d’un muscle dénervé

Aim. – The purpose of this revue is to focus on research concerning the effect of chronic muscle electrical stimulation after denervation and reinnervation.Actuality. – The therapeutic use of electricity date back to ancient times, when the greeks used electric eels to treat physical ailment. Today electrotherapy is very commonly applied by certified athletic trainers. Alpha motor neurons conduct impulses from the spinal cord to the muscle. When the conduction of impulses to muscle is disrupted, the individual loses control of the affected muscle. When the nerve to the muscle is not functioning, the muscle is denervated, or without innervation. Unlike nerve fibers in the central nervous system, peripheral nerve fibers can regenerate and active control of the muscle can be restored.Perspectives and projects. – The efficacy of electrical stimulation of denervated muscle has not been established in human. Electrical stimulation does not bring about reinnervation; however a regularly stimulated muscle may recover force-generating capacity sooner if reinnervation occurs. In mammals, it has been show since several years that the regular stimulation of a denervated and reinnervated muscle promoted the motor function return. Recently, it has also been observed in animals, that muscle stimulation with a biphasic current was responsible to a more rapid return of the muscle sensibility. However, these preliminary works realized in the young mammals need to be improved.     

Le chémoréflexe des membres inférieurs élève le débit sanguin et la consommation d'oxygène musculaire au début d'un exercice modéré des membres supérieurs

Aim – Test the hypothesis that increases in forearm blood flow (FBF) during the adaptive phase at the onset of moderate exercise would allow a more rapid increase in muscle oxygen uptake (VO_2mus).Materials and methods– Nine subjects completed forearm exercise in control (Ref) and leg occlusion (Occ) conditions. In Occ, exercise of ischemic calf muscles was performed prior to the onset of forearm exercise to activate the muscle chemoreflex evoking a 25 mmHg increase in mean arterial pressure that was sustained during forearm exercise.Results – A higher VO_2mus accompanied the higher FBF during the adaptive phase of the Occ tests, yet there was no difference in the baseline or steady state VO_2mus between Occ and Ref. Supplying more blood flow at the onset of exercise allowed a more rapid increase in oxidative phosphorylation supporting our hypothesis that, at least for this type of exercise, O₂ supply is rate limiting.     

Un test de terrain simple pour la détermination du seuil anaérobie

Aim – Validate a simple and indirect methodology which supplies a reliable estimate of the run velocity correspondent to the anaerobic threshold.Materials and methods – Twelve subjects took part to this study and each subject was asked to perform a maximum test on 1000, 1500, 2000 and 3000 m. For each athlete was calculate the straight line which joins the values of run tests on 1000 and 1500 and the values on the run tests on 2000 and 3000 m, moreover, the linear regression line interpolating the run values of the 4 tests was calculated. The value of the equation coefficient b of the 2 straight lines and of the regression line was considered the value correspondent to the velocity of the anaerobic threshold. Then each athlete was asked to perform 20 min of continuous run at the 3 various run velocities previously calculated. During the tests previously mentioned the production of haematic lactate was analysed.Results – The 2000 and 3000 m distances are the most suitable to determine the velocity of the anaerobic threshold.