Keller T S, Colloca C J, Fuhr A W
Department of Mechanical Engineering, University of Vermont, Burlington, VT 05405, USA.
J Manipulative Physiol Ther. 2000 Oct;23(8):521-30. doi: 10.1067/mmt.2000.109680.
The objective of this study was to quantify the mobility characteristics (dynamic stiffness and mechanical impedance) of the normal human thoracolumbar spine with a transient vibration analysis technique.
This study is a prospective clinical investigation to obtain normative biomechanical data from the human male and female spine in vivo.
Musculoskeletal research laboratory, university setting.
Twenty asymptomatic subjects (age range, 20-60 years) with no recent history of musculoskeletal complaints.
Mechanical impedance, effective stiffness, and resonant frequency analyses were used to quantify the dynamic stiffness of the thoracolumbar spine in this subject population. Data were obtained from posteroanterior mechanical thrusts delivered with an activator adjusting instrument equipped with a load cell and accelerometer by means of a portable computer.
In response to the activator adjusting instrument thrusts, the thoracolumbar spine typically exhibited an impedance minimum at frequencies ranging between 30 and 50 Hz. The maximum posteroanterior impedance and corresponding maximum effective stiffness of the thoracolumbar spine and sacrum was roughly 2 to 8 times greater than the magnitude of the impedance minimum. Statistically significant differences in mobility between male and female subjects were noted, particularly for frequencies corresponding to the maximum mobility (40 Hz) and minimum mobility (10-20 Hz, 70-80 Hz). For most subjects (both male and female), the lumbar region exhibited a higher impedance and stiffness (less mobility) when compared with the thoracic region.
The posteroanterior mechanical behavior of the human thoracolumbar spine was found to be sensitive to mechanical stimulus frequency and showed significant region-specific and gender differences. In the frequency range of 30 to 50 Hz, the lumbar spine of this subject population is the least stiff and therefore has the greatest mobility. From a biomechanical point-of-view, the results of this study indicate that dynamic spinal manipulative therapy procedures will produce more spinal motion for a given force, particularly when the posteroanterior manipulative thrust is delivered in frequency ranges at or near the resonant frequency. In this regard, spinal manipulative therapy procedures designed to target the resonant frequency of the spine require less force application. Both magnitude and frequency content of manual and mechanical thrusting manipulations may be critical elements for therapeutic outcome.
本研究的目的是采用瞬态振动分析技术量化正常人体胸腰椎的活动特性（动态刚度和机械阻抗）。
本研究是一项前瞻性临床调查，旨在获取人体男性和女性脊柱在体内的标准生物力学数据。
大学环境中的肌肉骨骼研究实验室。
20名无症状受试者（年龄范围20 - 60岁），近期无肌肉骨骼疾病史。
采用机械阻抗、有效刚度和共振频率分析来量化该受试者群体胸腰椎的动态刚度。数据通过配备称重传感器和加速度计的激活器调整仪器，借助便携式计算机，从前后方向的机械推力中获取。
响应激活器调整仪器的推力时，胸腰椎通常在30至50赫兹的频率范围内呈现阻抗最小值。胸腰椎和骶骨的最大前后阻抗以及相应的最大有效刚度大约比阻抗最小值大2至8倍。注意到男性和女性受试者在活动度方面存在统计学上的显著差异，特别是在对应最大活动度（40赫兹）和最小活动度（10 - 20赫兹、70 - 80赫兹）的频率上。对于大多数受试者（男性和女性），与胸椎区域相比，腰椎区域表现出更高的阻抗和刚度（活动度更小）。
发现人体胸腰椎的前后机械行为对机械刺激频率敏感，并表现出显著的区域特异性和性别差异。在30至50赫兹的频率范围内，该受试者群体的腰椎刚度最小，因此活动度最大。从生物力学角度来看，本研究结果表明，对于给定的力，动态脊柱手法治疗程序将产生更多的脊柱运动，特别是当前后手法推力在共振频率或接近共振频率的范围内施加时。在这方面，旨在针对脊柱共振频率的脊柱手法治疗程序需要施加的力更小。手法和机械推力操作的大小和频率成分可能是治疗效果的关键因素。
