From the Laboratório de Pesquisa do Exercício, Escola de Educação Física, Fisioterapia e Dança, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brasil (RR, MF, MAV); Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milan, Italy (RR); and Human Performance Laboratory, Schulthess Clinic, Zurich, Switzerland (NAM).
Am J Phys Med Rehabil. 2021 Feb 1;100(2):161-167. doi: 10.1097/PHM.0000000000001541.
The aim of the study was to determine the influence of neuromuscular electrical stimulation pulse waveform and frequency on evoked torque, stimulation efficiency, and discomfort at two neuromuscular electrical stimulation levels.
This is a repeated measures study. The quadriceps muscle of 24 healthy men was stimulated at submaximal (neuromuscular electrical stimulationsub) and maximal (neuromuscular electrical stimulationmax) levels using two pulse waveforms (symmetrical, asymmetrical) and three pulse frequencies (60, 80, 100 Hz). Repeated measures analysis of variance and effect sizes were used to verify the effect of pulse waveform and pulse frequency on stimulation efficiency (evoked torque/current intensity) and discomfort and to assess the magnitude of the differences, respectively.
Stimulation efficiency was higher for symmetrical (neuromuscular electrical stimulationsub = 0.88 ± 0.21 Nm/mA; neuromuscular electrical stimulationmax = 1.27 ± 0.46 Nm/mA) compared with asymmetrical (neuromuscular electrical stimulationsub = 0.77 ± 0.21 Nm/mA; neuromuscular electrical stimulationmax = 1.02 ± 0.34 Nm/mA; P ≤ 0.001; effect size = 0.56-0.66) but did not significantly differ between frequencies (P = 0.17). At both neuromuscular electrical stimulation levels, there were no statistically significant differences in discomfort between pulse waveforms or frequencies.
The higher stimulation efficiency of symmetrical pulses suggests that this waveform would be preferred to asymmetrical pulses in clinical practice. Stimulation frequencies between 60 and 100 Hz can be used interchangeably because of similar efficiency and discomfort.
本研究旨在确定神经肌肉电刺激脉冲波形和频率对两种神经肌肉电刺激水平下诱发扭矩、刺激效率和不适感的影响。
这是一项重复测量研究。使用两种脉冲波形（对称、不对称）和三种脉冲频率（60、80、100 Hz）对 24 名健康男性的股四头肌进行亚最大（神经肌肉电刺激 sub）和最大（神经肌肉电刺激 max）刺激。重复测量方差分析和效应量用于验证脉冲波形和脉冲频率对刺激效率（诱发扭矩/电流强度）和不适感的影响，并分别评估差异的大小。
对称脉冲（神经肌肉电刺激 sub = 0.88 ± 0.21 Nm/mA；神经肌肉电刺激 max = 1.27 ± 0.46 Nm/mA）的刺激效率高于不对称脉冲（神经肌肉电刺激 sub = 0.77 ± 0.21 Nm/mA；神经肌肉电刺激 max = 1.02 ± 0.34 Nm/mA；P ≤ 0.001；效应量 = 0.56-0.66），但在频率之间没有显著差异（P = 0.17）。在两种神经肌肉电刺激水平下，脉冲波形或频率之间的不适感没有统计学上的显著差异。
对称脉冲的更高刺激效率表明，在临床实践中，这种波形将优先于不对称脉冲。由于效率和不适感相似，60 至 100 Hz 之间的刺激频率可以互换使用。
