Exercise Research Laboratory, School of Physical Education, Physical Therapy and Dance, Federal University of Rio Grande do Sul, Porto Alegre, RS,Brazil.
Health School, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS,Brazil.
J Sport Rehabil. 2023 Feb 22;32(5):540-548. doi: 10.1123/jsr.2022-0159. Print 2023 Jul 1.
Pulsed current and kilohertz frequency alternating current are 2 types of neuromuscular electrical stimulation (NMES) currents often used by clinicians during rehabilitation. However, the low methodological quality and the different NMES parameters and protocols used in several studies might explain their inconclusive results in terms of their effects in the evoked torque and the discomfort level. In addition, the neuromuscular efficiency (ie, the NMES current type that evokes the highest torque with the lowest current intensity) has not been established yet. Therefore, our objective was to compare the evoked torque, current intensity, neuromuscular efficiency (evoked torque/current intensity ratio), and discomfort between pulsed current and kilohertz frequency alternating current in healthy people.
A double-blind, randomized crossover trial.
Thirty healthy men (23.2 [4.5] y) participated in the study. Each participant was randomized to 4 current settings: 2 kilohertz frequency alternating currents with 2.5 kHz of carrier frequency and similar pulse duration (0.4 ms) and burst frequency (100 Hz) but with different burst duty cycles (20% and 50%) and burst durations (2 and 5 ms); and 2 pulsed currents with similar pulse frequency (100 Hz) and different pulse duration (2 and 0.4 ms). The evoked torque, current intensity at the maximal tolerated intensity, neuromuscular efficiency, and discomfort level were evaluated.
Both pulsed currents generated higher evoked torque than the kilohertz frequency alternating currents, despite the similar between-currents discomfort levels. The 2 ms pulsed current showed lower current intensity and higher neuromuscular efficiency compared with both alternated currents and with the 0.4 ms pulsed current.
The higher evoked torque, higher neuromuscular efficiency, and similar discomfort of the 2 ms pulsed current compared with 2.5-kHz frequency alternating current suggests this current as the best choice for clinicians to use in NMES-based protocols.
脉冲电流和千赫兹频率交流电是临床医生在康复过程中经常使用的两种神经肌肉电刺激（NMES）电流。然而，由于几项研究中 NMES 参数和方案的方法学质量较低，以及结果不一致，其在诱发扭矩和不适水平方面的效果仍不确定。此外，神经肌肉效率（即，用最低电流强度产生最高扭矩的 NMES 电流类型）尚未确定。因此，我们的目的是比较健康人在脉冲电流和千赫兹频率交流电之间的诱发扭矩、电流强度、神经肌肉效率（诱发扭矩/电流强度比）和不适。
双盲、随机交叉试验。
30 名健康男性（23.2[4.5]岁）参与了这项研究。每位参与者随机接受 4 种电流设置：2 种千赫兹频率交流电，载波频率为 2.5kHz，脉冲持续时间（0.4ms）和脉冲频率（100Hz）相似，但脉冲占空比（20%和 50%）和脉冲宽度（2ms 和 5ms）不同；2 种脉冲电流，脉冲频率相似（100Hz），脉冲持续时间不同（2ms 和 0.4ms）。评估了诱发扭矩、最大耐受强度下的电流强度、神经肌肉效率和不适水平。
尽管两种交流电之间的不适水平相似，但两种脉冲电流产生的诱发扭矩均高于交流电。与两种交替电流和 0.4ms 脉冲电流相比，2ms 脉冲电流的电流强度较低，神经肌肉效率较高。
与 2.5kHz 频率交流电相比，2ms 脉冲电流具有更高的诱发扭矩、更高的神经肌肉效率和相似的不适，这表明该电流是临床医生在基于 NMES 的方案中使用的最佳选择。
