Electrical Stimulation Superimposed onto Voluntary Muscular Contraction

Abstract

Electrical stimulation (ES) reverses the order of recruitment of motor units (MU) observed with voluntary muscular contraction (VOL) since under ES, large MU are recruited before small MU. The superimposition of ES onto VOL (superimposed technique: application of an electrical stimulus during a voluntary muscle action) can theoretically activate more motor units than VOL performed alone, which can engender an increase of the contraction force. Two superimposed techniques can be used: (i) the twitch interpolation technique (ITT), which consists of interjecting an electrical stimulus onto the muscle nerve; and (ii) the percutaneous superimposed electrical stimulation technique (PST), where the stimulation is applied to the muscle belly. These two superimposed techniques can be used to evaluate the ability to fully activate a muscle. They can thus be employed to distinguish the central or peripheral nature of fatigue after exhausting exercise. In general, whatever the technique employed, the superimposition of ES onto volitional exercise does not recruit more MU than VOL, except with eccentric actions. Nevertheless, the neuromuscular response associated with the use of the superimposed technique (ITT and PST) depends on the parameter of the superimposed current. The sex and the training level of the subjects can also modify the physiological impact of the superimposed technique. Although the motor control differs drastically between training with ES and VOL, the integration of the superimposed technique in training programmes with healthy subjects does not reveal significant benefits compared with programmes performed only with voluntary exercises. Nevertheless, in a therapeutic context, training programmes using ES superimposition compensate volume and muscle strength deficit with more efficiency than programmes using VOL or ES separately.

Knee Extension and Flexion Weakness in People With Knee Osteoarthritis: Is Antagonist Cocontraction a Factor?

“…25 A CAR of 1.0 implies that the muscle is fully activated through voluntary contraction, with no additional force obtained from the stimulus. Although both methods have been used in subjects with knee OA, the burst superimposition technique is the recommended technique during maximal contractions, 38,45 due to trains of stimuli having greater sensitivity to activation deficiencies than superimposed single or double stimuli. 25 A loss of knee extension and/or flexion strength, often interpreted as muscle weakness, may be a consequence of increased antagonist muscle activation.…”

“…We chose to use the burst superimposition technique due to its recommendation for use when undertaking maximal strength trials. 38,45 Studies of muscle activation in individuals with knee OA using this method have provided mixed results, possibly due to methodological, disease status, and participant age differences. Three studies of muscle inhibition in subjects with endstage knee OA, using the burst superimposition technique, have reported CAR values substantially less than the 0.94 to 0.95 values considered normal for healthy older adults.…”

Efecto del entrenamiento combinado de pliometría y electroestimulación en salto vertical. (Effect of combined plyometric and electrostimulation training on vertical jump).

“…Se realizó el anterior procedimiento debido a que las diferencias de excitabilidad del vasto interno y el externo hacen necesaria la utilización de dos canales diferentes de EE NM (Coarasa et al, 2000), ya que la utilización de un sólo canal podría provocar desequilibrios musculares (Cometti, 1998). Se colocó el electrodo activo en el punto motor del músculo (Paillard et al, 2006;Babault et al, 2007;Benito, 2008), y el otro en la zona proximal, a la altura del triángulo femoral (Vanderthommen y Crielaard, 2001;Holcomb, 2005). Los electrodos fueron colocados, siguiendo este protocolo, por tres personas instruidas y entrenadas previamente.…”

“…Otro aspecto controvertido en la aplicación de la EE NM ha sido la frecuencia (Hz) a emplear Child, Brown, Day, Saxton, y Donnehy (1998), Meaños, Alonso, Sánchez, y Téllez, (2002), aunque finalmente, las frecuencias entre 70 y 120 Hz son las más empleadas para aumentar la fuerza explosiva y las comprendidas entre 120 y 150 Hz las utilizadas para mejorar la fuerza explosiva-elástica (Maffiuletti, Cometti, Amiridis, Martin, Pousson, y Chatard, 2000;Vanderthommen y Crielaard, 2001;Valli, Boldrini, Bianchedi, Brizzi, y Miserocchi, 2002;Gondin, Guetie, Ballay, y Martin, 2006;Lyons, Robb, Irrgang, y Fitzgerald, 2005;Paillard, Noé, Passelergue, y Dupui, 2006;Toca-Herrera, Gallach, Gómis y González, 2008).…”

Electrical stimulation and isokinetic training: effects on strength and neuromuscular properties of healthy young adults

“…Unfortunately, the abundance of muscle stimulators and NMES protocols in clinics appears to contrast sharply with the availability and quality of evidence regarding their efficacy. The available evidence is of limited quality and needs to be interpreted with caution [8][9][10] . Strength training is routinely used in rehabilitation and sports activities to improve musculoskeletal performance.…”