Graduate Program in Rehabilitation Sciences, Universidade de Brasília, Brasília, DF, Brazil.
Graduate Program of Sciences and Technology of Health, Universidade de Brasília, Brasília, DF, Brazil.
Braz J Phys Ther. 2021 Sep-Oct;25(5):593-600. doi: 10.1016/j.bjpt.2021.03.001. Epub 2021 Mar 26.
Neuromuscular electrical stimulation (NMES) is an important therapeutic tool for rehabilitation. However, best stimulation parameters remain to be determined.
To determine the influence of different electrical stimulation currents and phase durations on torque, efficiency, and discomfort.
Using a cross-over design, kHz frequency alternating currents (KFAC) and pulsed currents (PC) with narrow (200 µs) or wide (500 µs) phase durations were randomly applied on knee extensor muscles of healthy participants with a minimum of seven days between sessions. The NMES-evoked torque, NMES-efficiency, and discomfort (visual 0-10 cm analogue scale) were measured for each stimulation intensity increments (10 mA). Statistics were conducted using a three-way analysis of variances (phase duration x current x intensity), followed by Tukey post-hoc.
Twenty-four males (age 22.3 ± 3.5years) were included. No effect of NMES current was observed for torque, efficiency, and discomfort. For wide phase durations (500 µs), torque significantly increased for all stimulation intensities. For narrow phase durations (200 µs) evoked torque significantly increased only after 40% of maximal stimulation intensity. Phase durations of 500 µs produced greater torque than 200 µs. Discomfort was greater with 500 µs when compared to 200 µs. Submaximal relative torque, for example 40% of maximum voluntary contraction (MVC), was obtained with ∼ 60% and ∼ 80% of the maximal current intensity for 500 µs and 200 µs, respectively.
KFAC and PC current applied with the same phase duration induced similar relative submaximal and maximum evoked-torque, efficiency, and perceived discomfort. However, currents with 500 µs induced higher evoked-torque, current efficiency, and perceived discomfort.
神经肌肉电刺激（NMES）是康复的重要治疗工具。然而，最佳刺激参数仍有待确定。
确定不同电刺激电流和相位持续时间对扭矩、效率和不适的影响。
使用交叉设计，在健康参与者的膝关节伸肌上随机应用 kHz 频率交流电（KFAC）和脉冲电流（PC），相位持续时间分别为窄（200µs）或宽（500µs），两次治疗之间至少间隔 7 天。对于每个刺激强度增量（10mA），测量 NMES 诱发的扭矩、NMES 效率和不适（视觉 0-10cm 模拟量表）。使用三向方差分析（相位持续时间 x 电流 x 强度）进行统计学分析，然后进行 Tukey 事后检验。
共纳入 24 名男性（年龄 22.3±3.5 岁）。NMES 电流对扭矩、效率和不适均无影响。对于宽相位持续时间（500µs），所有刺激强度的扭矩均显著增加。对于窄相位持续时间（200µs），仅在 40%最大刺激强度后，诱发扭矩才显著增加。500µs 的相位持续时间产生的扭矩大于 200µs。与 200µs 相比，500µs 时的不适感更大。例如，对于 40%的最大自主收缩（MVC）的相对亚最大扭矩，500µs 和 200µs 分别需要约 60%和 80%的最大电流强度。
应用相同相位持续时间的 KFAC 和 PC 电流会引起相似的相对亚最大和最大诱发扭矩、效率和感知不适。然而，500µs 的电流会引起更高的诱发扭矩、电流效率和感知不适。
