The superficial hip adductor muscles are situated in close proximity to each other. Therefore, relative movement between the overlying skin and the muscle belly could lead to a shift in the position of surface electromyography (EMG) electrodes and contamination of EMG signals with activity from neighboring muscles. The aim of this study was to explore whether hip movements or isometric contraction could lead to relative movement between the overlying skin and 3 adductor muscles: adductor magnus, adductor longus, and adductor gracilis. The authors also sought to investigate isometric torque–EMG relationships for the 3 adductor muscles. Ultrasound measurement showed that EMG electrodes maintained a position which was at least 5 mm within the muscle boundary across a range of hip flexion–extension angles and across different contraction levels. The authors also observed a linear relationship between torque and EMG amplitude. This is the first study to use ultrasound to track the relative motion between skin and muscle and provides new insight into electrode positioning. The findings provide confidence that ultrasound-based positioning of EMG electrodes can be used to derive meaningful information on output from the adductor muscles and constitute a step toward recognized guidelines for surface EMG measurement of the adductors.

浅表髋内收肌彼此非常接近。因此，上层皮肤和肌腹之间的相对运动可能会导致表面肌电图 (EMG) 电极的位置发生变化，并导致邻近肌肉活动对 EMG 信号的污染。本研究的目的是探讨髋部运动或等长收缩是否会导致覆盖皮肤和 3 个内收肌（大收肌、长收肌和股薄肌）之间的相对运动。作者还试图研究 3 块内收肌的等长扭矩与肌电图关系。超声测量显示肌电图电极在一系列髋关节屈伸角度和不同收缩水平上保持在肌肉边界内至少 5 毫米的位置。作者还观察到扭矩和肌电图振幅之间存在线性关系。这是第一项使用超声波跟踪皮肤和肌肉之间的相对运动的研究，并为电极定位提供了新的见解。这些发现提供了信心，即基于超声的肌电图电极定位可用于获取有关内收肌输出的有意义的信息，并为内收肌表面肌电图测量的公认指南迈出了一步。