Neumann D A
Department of Physical Therapy, Marquette University, Milwaukee, WI 53201-1881, USA.
Phys Ther. 1996 Dec;76(12):1320-30. doi: 10.1093/ptj/76.12.1320.
Carrying loads in one hand may result in the hip abductor (HA) muscles needing to generate large forces. For a person with a prosthetic hip, these forces may contribute to loosening of the implant. In this study, surface electromyography (EMG) was used to estimate the relative demands placed on the HA muscles as persons with a prosthetic hip carried loads in one hand.
Twenty-five active subjects (9 female, 16 male) with a prosthetic hip participated. Subjects were aged 40 to 86 years (mean = 63.7, SD = 10.7).
Surface EMG data from the HA muscles (primarily the gluteus medius) were analyzed during mid-stance as subjects carried loads weighing 5%, 10%, and 15% of their body weight. Loads were carried in the hand opposite the side of the prosthetic hip (contralaterally held loads) or in the hand on the same side as the prosthetic hip (ipsilaterally held loads).
Results showed that the contralaterally held loads produced greater HA muscle EMG activity levels than no-load walking. The ipsilaterally held loads produced lower HA muscle EMG activity levels than no-load walking.
These EMG data, in addition to calculations using a simple biomechanical model, suggest that persons should use caution or avoid carrying loads in the hand on the side contralateral to their prosthetic hip.
单手负重可能导致髋外展肌（HA）需要产生较大力量。对于佩戴人工髋关节的人来说，这些力量可能会导致植入物松动。在本研究中，表面肌电图（EMG）被用于评估佩戴人工髋关节的人单手负重时HA肌肉所承受的相对负荷。
25名佩戴人工髋关节的活跃受试者（9名女性，16名男性）参与了研究。受试者年龄在40至86岁之间（平均 = 63.7，标准差 = 10.7）。
在受试者单手持重相当于其体重5%、10%和15%的物体时，于站立中期分析HA肌肉（主要是臀中肌）的表面肌电图数据。重物拿在与人工髋关节相对侧的手中（对侧手持重物）或与人工髋关节同侧的手中（同侧手持重物）。
结果显示，对侧手持重物时HA肌肉的肌电图活动水平高于无负重行走时。同侧手持重物时HA肌肉的肌电图活动水平低于无负重行走时。
这些肌电图数据，以及使用简单生物力学模型进行的计算表明，人们应该谨慎或避免在与人工髋关节对侧的手中负重。
