Université Clermont Auvergne, Laboratoire des Adaptations Métaboliques à l'Exercice en conditions Physiologiques et Pathologiques (AME2P), Clermont-Ferrand, France.
Université d'Evry-Val-d'Essonne/Genopole, Unité de Biologie Intégrative des Adaptations à l'Exercice, Evry, France.
J Sports Sci Med. 2019 Nov 19;18(4):674-679. eCollection 2019 Dec.
The aim of the present study was to compare the recruitment of the antagonist muscles and its effect on the measurement of the voluntary activation level (VA) of the knee extensor (KE) muscles for different anode placements used to stimulate the femoral nerve. We hypothesized that when the anode is positioned over the gluteal fold (GF), the antagonist muscles recruitment would be greater and, thus the VA overestimated, than when the anode is placed midway between the greater trochanter and the lower border of the iliac crest (Mid). Thirteen healthy men (23 ± 4 yr) were tested in both conditions (GF vs. Mid) in a randomized order. Recruitment curves were performed to determine the optimal stimulus intensity (I) and quantify antagonist muscles recruitment (i.e. biceps femoris M-wave). Participants performed maximal voluntary isometric contractions (MVIC) and the interpolated twitch technique was used to measured VA. Antagonist muscles recruitment was greater when the anode was placed over the GF than Mid. The I was also lower for GF than Mid placement. However, no significant effect of anode placement was found for the interpolated twitch technique outcome. When the anode was placed over the GF, antagonist muscles recruitment was greater, inducing optimal stimulus intensity underestimation. However, it did not affect VA assessment. To fully avoid this potential limitation, Mid anode placement should nevertheless be preferred for the KE neuromuscular function assessment, owing to the reduced recruitment of the antagonist muscles.
本研究旨在比较不同股神经刺激阳极位置对拮抗肌募集的影响及其对膝关节伸肌（KE）肌肉的自愿激活水平（VA）测量的影响。我们假设当阳极置于臀褶（GF）上方时，拮抗肌募集量会更大，从而高估 VA，而当阳极置于大转子和髂嵴下缘之间的中点（Mid）时则不会。13 名健康男性（23±4 岁）以随机顺序在两种情况下（GF 与 Mid）进行测试。进行募集曲线以确定最佳刺激强度（I）并量化拮抗肌募集（即股二头肌 M 波）。参与者进行最大随意等长收缩（MVIC），并使用插值抽搐技术测量 VA。当阳极置于 GF 时，拮抗肌募集量大于 Mid 时。GF 的 I 也低于 Mid 放置。然而，插值抽搐技术结果没有发现阳极位置的显著影响。当阳极置于 GF 时，拮抗肌募集量增加，导致最佳刺激强度低估。然而，它并没有影响 VA 的评估。为了完全避免这种潜在的限制，由于拮抗肌募集减少，KE 神经肌肉功能评估仍应首选 Mid 阳极放置。
