Reeves N Peter, Cholewicki Jacek, Milner Theodore, Lee Angela S
Center for Orthopedic Research, Osteopathic Surgical Specialties, College of Osteopathic Medicine, Michigan State University, Ingham Regional Orthopedic Hospital, 2727 S. Pennsylvania Ave., Rm 230, Lansing, MI 48910, USA.
Exp Brain Res. 2008 Jul;188(3):457-63. doi: 10.1007/s00221-008-1378-9. Epub 2008 Apr 29.
The goal of this paper was to determine if trunk antagonist activation is associated with impaired neuromuscular performance. To test this theory, we used two methods to impair neuromuscular control: strenuous exertions and fatigue. Force variability (standard deviation of force signal) was assessed for graded isometric trunk exertions (10, 20, 40, 60, 80% of max) in flexion and extension, and at the start and end of a trunk extensor fatiguing trial. Normalized EMG signals for five trunk muscle pairs (RA rectus abdominis, EO external oblique, IO internal oblique, TE thoracic erector spinae, and LE lumbar erector spinae) were collected for each graded exertion, and at the start and end of a trunk extensor fatiguing trial. Force variability increased for more strenuous exertions in both flexion (P < 0.001) and extension (P < 0.001), and after extensor fatigue (P < 0.012). In the flexion direction, both antagonist muscles (TE and LE) increased activation for more strenuous exertions (P < 0.001). In the extension direction, all antagonist muscles except RA increased activation for more strenuous exertions (P < 0.05) and following fatigue (P < 0.01). These data demonstrate a strong relationship between force variability and antagonistic muscle activation, irrespective of where this variability comes from. Such antagonistic co-activation increases trunk stiffness with the possible objective of limiting kinematic disturbances due to greater force variability.
本文的目的是确定躯干拮抗肌激活是否与神经肌肉功能受损有关。为了验证这一理论，我们使用了两种方法来损害神经肌肉控制：剧烈运动和疲劳。在躯干屈伸的分级等长运动（最大力量的10%、20%、40%、60%、80%）中，以及在躯干伸肌疲劳试验开始和结束时，评估力量变异性（力量信号的标准差）。在每次分级运动以及躯干伸肌疲劳试验开始和结束时，收集五对躯干肌肉（腹直肌、腹外斜肌、腹内斜肌、胸段竖脊肌和腰段竖脊肌）的标准化肌电图信号。在屈伸运动中，随着运动强度增加，力量变异性均增加（屈曲时P<0.001，伸展时P<0.001），伸肌疲劳后力量变异性也增加（P<0.012）。在屈曲方向，两种拮抗肌（胸段竖脊肌和腰段竖脊肌）在运动强度增加时激活增强（P<0.001）。在伸展方向，除腹直肌外，所有拮抗肌在运动强度增加时（P<0.05）以及疲劳后（P<0.01）激活均增强。这些数据表明，无论力量变异性来自何处，力量变异性与拮抗肌激活之间都存在密切关系。这种拮抗肌共同激活会增加躯干僵硬度，可能目的是限制因更大的力量变异性而导致的运动干扰。
