Gorgey Ashraf S, Wadee Amir N, Sobhi Nagi N
Department of Physical Therapy, Indiana University, Indianapolis, Indiana 46202, USA.
Photomed Laser Surg. 2008 Oct;26(5):501-6. doi: 10.1089/pho.2007.2161.
The purpose of this pilot study is to determine if low-level laser therapy (LLLT) could attenuate skeletal muscle fatigue induced by surface neuromuscular electrical stimulation (NMES) in healthy volunteers.
Five college-age participants underwent three cross-over randomized trials: two (LLLT + NMES) test trials and a control trial (NMES only), in which NMES was applied to their dominant knee extensor muscle group. The LLLT doses, 500 mW at 808 nm, were either adjusted to deliver a total energy of 7 J for 10 min or 3 J for 5 min in a blinded fashion. Following LLLT irradiation, the NMES protocol was immediately delivered for 3 min to induce fatigue in the knee extensor muscle group.
The five participants completed the three trials. After the control trial, torque significantly decreased (62%; p < 0.0001) at the end of 3 min. There was no significant difference between the 7 J and 3 J trials on muscle fatigue. Following both LLLT trials, torque significantly decreased (51%; p < 0.0001) at the end of 3 min. Although there was a difference (11%) in fatigue between the two LLLT trials and the control trial, this difference did not attain statistical significance (p = 0.63).
LLLT did not attenuate muscle fatigue evoked by NMES, but this needs to be further addressed in human studies and clinical settings. The lack of significant findings could be explained by the small sample size and the selection of LLLT parameters.
本初步研究的目的是确定低强度激光疗法（LLLT）是否能减轻健康志愿者因表面神经肌肉电刺激（NMES）引起的骨骼肌疲劳。
五名大学年龄的参与者进行了三项交叉随机试验：两项（LLLT + NMES）测试试验和一项对照试验（仅NMES），其中NMES应用于其优势膝伸肌肌群。以盲法将808 nm波长、500 mW的LLLT剂量调整为在10分钟内传递7 J的总能量或在5分钟内传递3 J的总能量。在LLLT照射后，立即进行3分钟的NMES方案以诱导膝伸肌肌群疲劳。
五名参与者完成了三项试验。对照试验后，3分钟结束时扭矩显著下降（62%；p < 0.0001）。7 J试验和3 J试验在肌肉疲劳方面无显著差异。在两项LLLT试验后，3分钟结束时扭矩显著下降（51%；p < 0.0001）。尽管两项LLLT试验与对照试验在疲劳方面存在差异（11%），但该差异未达到统计学显著性（p = 0.63）。
LLLT并未减轻NMES诱发的肌肉疲劳，但这需要在人体研究和临床环境中进一步探讨。缺乏显著结果可能是由于样本量小和LLLT参数的选择所致。
