V-wave

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The V-wave is triggered by supramaximal electrical stimulation of a peripheral nerve during maximal, voluntary muscle contraction . The V-wave can be used to quantify the neuronal activation of the muscle .

Basics

Supramaximal electrical stimulation of a peripheral nerve (e.g. tibial nerve ) can be used to observe a second potential in the OEMG during a maximum, voluntary contraction in addition to the direct muscle response ( M wave ) . This electrophysiological variation of the H wave is referred to as the V wave (voluntary wave).

From a certain stimulation intensity onwards, the H-wave decreases due to the collision of the afferent action potential with the antidromic action potential. The collision takes place in the efferent nerve fibers due to the different conduction speeds of Ia-afferent nerve fibers and efferent nerve fibers. Under maximum, voluntary contraction, natural efferent action potentials can collide with the artificially evoked antidromic action potentials. This enables the peripheral evoked signal to return to the homonymous muscle via the monosynaptic circuit in the spinal cord via the ɑ motor neuron . This muscle action potential corresponds to that of the H-wave, but is defined as the V-wave, since it was produced under maximum contraction. With increasing motor neuronal activity, the antidromic action potential is increasingly suppressed. This leads to an increase in the peak-to-peak amplitude of the V-wave. From the ratio of the maximum M-wave and the V-wave (V / M), conclusions could be drawn about the extent of the efferent, ɑ-motor neuronal output.

Individual evidence

  1. ↑ Fimland, M., Helgerud, J., Gruber, M., Leivseth, G. & Hoff, J. (2009). Functional maximal strength training induces neural transfer to single-joint tasks. European Journal of Applied Physiology 107, pp. 21-29.
  2. ↑ Aagaard, P., Simonsen, EB, Andersen, JL, Magnusson, P. & Dhyre-Poulsen, P. (2002). Neural adaptation to resistance training. Changes in evoked V-wave and H-reflex responses. Journal of Applied Physiology, 92, pp. 2309-2318.

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