A influência do tamanho do eletrodo e da espessura da dobra cutânea no pico de torque isométrico de quadríceps e no desconforto sensorial durante a eletroestimulação neuromucular em indivíduos saudáveis.

Abstract

Introduction: Neuromuscular electrical stimulation (NMES) is used in rehabilitation to promote muscle strength gains and prevent atrophy. Some factors can influence the transmission of electrical current and consequently the generation of the evoked isometric torque peak (EPT), such as skinfold thickness (EDC), electrode size and discomfort perceived during therapy application. These factors can affect the effectiveness of NMES and compromise rehabilitation results. Objective: To investigate the influence of electrode size and skinfold thickness on the quadriceps evoked isometric torque peak and on sensory discomfort in healthy individuals during NMES. Methods: It is characterized as an observational, analytical and longitudinal study. 40 individuals of both sexes were evaluated, recruited at the Federal University of Bahia and selected through non-probabilistic means of convenience through invitation and the media. Individuals who had a previous record of surgeries or injuries in the limb to be evaluated, who were using medications that could interfere with the tests, were excluded from the research; such as analgesics, tranquilizers, antidepressants or other centrally acting agents. They also couldn't be allergic to latex and tape. Medical history was self-reported. Data collection was carried out on three different days, each day with an electrode size (P = 2x5cm, M = 5x5cm, G = 9x5cm) previously chosen by each participant. The muscle fibers were warmed up for three minutes with NMES, followed by the beginning of the protocol. The isometric torque peak evoked by NMES was measured using an isokinetic dynamometer. Results: PTIE by NMES in the group with smaller EDC (16.8 ± 5.49) and larger EDC (39.0 ± 8.57), using the three electrode sizes, showed a significant difference (p < 0.009; p < 0.022, respectively), however, in the comparison of PTIE by NMES between electrodes M and G, there was no significant difference (p = 0.734). In the group with higher EDC (39.0 ± 8.57), multiple comparisons showed a significant difference between all electrode sizes during NMES: P and M (p < 0.001), P and G (p < 0.001), M and G ( p < 0.006). Regarding the influence of EDC, of all study participants, on PTIE in the three electrode sizes, there was a negative correlation in all electrode sizes used during NMES, P, M and L respectively (r = - 0.466 and p = 0.002; r = -0.488 and p = 0.001; r = - 0.338 and p = 0.033), indicating that the higher the EDC, the lower the PTIE. Pain perceived during NMES showed no association with skinfold thickness in the 2 groups (smaller and larger EDC), in the 3 electrode sizes (p = 0.620; p = 0.952; and p = 0.824 respectively). Conclusion: Skinfold thickness had a negative influence on quadriceps PTIE, but there was no association with perceived sensory discomfort. And regarding the size of the electrode used during NMES, there is a need to evaluate the EDC measurement in order to choose the best size to improve the efficiency of the therapy.