Lanza Marcel B, Ryan Alice S, Gray Vicki, Perez William J, Addison Odessa
Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD, United States.
Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States.
Front Physiol. 2020 Dec 10;11:614415. doi: 10.3389/fphys.2020.614415. eCollection 2020.
The amount of tissue between the muscle and surface electromyography (sEMG) electrode influences the sEMG signals. Increased intramuscular adipose tissue (IMAT) of the hip abductor muscles negatively impacts balance in older individuals, but it is unknown if this is related to the ability to activate the muscles. The aim of this preliminary study was to investigate the influence of gluteus medius (GM) IMAT on sEMG amplitude during maximal voluntary isometric contractions (MVIC) of the hip abductors in older adults. We recruited 12 healthy community-dwelling older adults that underwent a spiral computerized tomography scan. High density lean (HDL), IMAT, and subcutaneous adipose tissue (SUBFAT) cross-sectional area of the GM were assessed. sEMG signal from the GM was recorded while participants performed an MVIC of the hip abductors. There was a negative correlation between GM activation and IMAT ( = -0.58, = 0.046), and also SUB ( = -0.78, = 0.002) and a positive correlation with HDL ( = 0.73, = 0.006). When controlling for SUB, the partial correlations demonstrated a consistent negative correlation between GM activation and IMAT ( = -0.60, = 0.050) but no relationship with HDL. The current results are important for helping to interpret the results from sEMG by accounting for IMAT. In conclusion, the neuromuscular activation of the GM may be reduced by the quantity of IMAT.
肌肉与表面肌电图（sEMG）电极之间的组织量会影响sEMG信号。髋外展肌的肌内脂肪组织（IMAT）增加会对老年人的平衡产生负面影响，但尚不清楚这是否与肌肉激活能力有关。这项初步研究的目的是调查臀中肌（GM）的IMAT对老年人髋外展肌最大自主等长收缩（MVIC）期间sEMG振幅的影响。我们招募了12名健康的社区居住老年人，他们接受了螺旋计算机断层扫描。评估了GM的高密度瘦肉（HDL）、IMAT和皮下脂肪组织（SUBFAT）横截面积。在参与者进行髋外展肌的MVIC时，记录来自GM的sEMG信号。GM激活与IMAT之间存在负相关（r = -0.58，P = 0.046），与SUB也存在负相关（r = -0.78，P = 0.002），与HDL存在正相关（r = 0.73，P = 0.006）。在控制SUB后，偏相关显示GM激活与IMAT之间存在一致的负相关（r = -0.60，P = 0.050），但与HDL无关系。目前的结果对于通过考虑IMAT来帮助解释sEMG结果很重要。总之，GM的神经肌肉激活可能会因IMAT的数量而降低。
