Kera Takeshi, Maruyama Hitoshi
Department of Physical Therapy, Health Science University, Yamanashi, Japan.
J Physiol Anthropol Appl Human Sci. 2005 Jul;24(4):259-65. doi: 10.2114/jpa.24.259.
The purpose of this study was to determine the influence of posture on the expiratory activity of the abdominal muscles. Fifteen young adult men participated in the study. Activities of the external oblique abdominis, internal oblique abdominis, and rectus abdominis muscles were measured electromyographically in various postures. We used a pressure threshold in order to activate the abdominal muscles as these muscles are silent at rest. A spirometer was used to measure the lung volume in various postures. Subjects were placed in the supine, standing, sitting, and sitting-with-elbow-on-the-knee (SEK) positions. Electromyographic activity and mouth pressure were measured during spontaneous breathing and maximal voluntary ventilation under the respiratory load. We observed that the lung volume changed with posture; however, the breathing pattern under respiratory load did not change. During maximal voluntary ventilation, internal oblique abdominis muscle expiratory activity was lower in the SEK position than in any other position, external oblique abdominis muscle inspiratory activity was lower in the supine position than in any other position, and internal oblique abdominis muscle activity was higher in the standing position than in any other position. During spontaneous breathing, external oblique abdominis muscle activity was higher during expiration and inspiration in the SEK position than in any other position. The internal oblique abdominis muscle activity was higher during both inspiration and expiration in the standing position than in any other position. The rectus abdominis muscle activity did not change with changes in posture during both inspiration and expiration. Increase in the external oblique abdominis activity in the SEK position was due to anatomical muscle arrangement that was consistent with the direction of lower rib movement. On the other hand, increase in the internal oblique abdominis activity in the standing position was due to stretching of the abdominal wall by the viscera. We concluded that differences in activity were due to differences in the anatomy of the abdominal muscles and the influence of gravity.
本研究的目的是确定姿势对腹部肌肉呼气活动的影响。15名年轻成年男性参与了该研究。通过肌电图测量了不同姿势下腹外斜肌、腹内斜肌和腹直肌的活动。由于这些肌肉在静息时不活动，我们使用了一个压力阈值来激活腹部肌肉。使用肺活量计测量不同姿势下的肺容积。受试者被置于仰卧位、站立位、坐位和肘膝位（SEK）。在呼吸负荷下的自主呼吸和最大自主通气过程中测量肌电图活动和口腔压力。我们观察到肺容积随姿势而变化；然而，呼吸负荷下的呼吸模式没有改变。在最大自主通气过程中，SEK位的腹内斜肌呼气活动低于其他任何位置，仰卧位的腹外斜肌吸气活动低于其他任何位置，站立位的腹内斜肌活动高于其他任何位置。在自主呼吸过程中，SEK位的腹外斜肌在呼气和吸气时的活动高于其他任何位置。站立位的腹内斜肌在吸气和呼气时的活动均高于其他任何位置。腹直肌的活动在吸气和呼气时均不随姿势变化而改变。SEK位腹外斜肌活动的增加是由于肌肉解剖结构与下肋骨运动方向一致。另一方面，站立位腹内斜肌活动的增加是由于内脏对腹壁的牵拉。我们得出结论，活动差异是由于腹部肌肉解剖结构的差异和重力的影响。
