Oliver M J, Twomey L T
Clin Biomech (Bristol). 1995 Oct;10(7):363-368. doi: 10.1016/0268-0033(95)00001-2.
This in vitro study was designed to examine extension creep of the lumbar spine under conditions of sustained loading. By means of a weight and pulley circuit, loads simulating lumbar extension and flexion were applied to 25 male lumbar spines removed at postmortem. Sagittal ranges of movement and the amount of creep occurring in a 20-min period at the limit of extension were recorded. The data were classified into three age group categories representing young adults, the middle-aged and the elderly. The results indicated that extension creep behaviour was similar to that of flexion creep previously reported. The elderly lumbar spines appeared to have a greater range of extension creep than those of the young and middle-aged groups, but analysis of variance showed that the difference in creep between age groups was not significant. The viscoelastic behaviour of the spinal ligaments, zygapophyseal joint capsules and intervertebral discs during extension are sufficient to produce a characteristic creep-recovery curve, but perhaps the important role that the zygapophyseal joints play in limiting extension is sufficient to prevent significant change in creep behaviour with increasing age. RELEVANCE:--This study provides information on the biomechanical responses of the lumbar spine to sustained end range extension loading. Results suggest that in the living, even brief periods of sustained extension loading may cause significant extension creep.
本体外研究旨在检测腰椎在持续负荷条件下的伸展蠕变情况。通过重物和滑轮装置，对25具死后移除的男性腰椎施加模拟腰椎伸展和屈曲的负荷。记录矢状面活动范围以及在伸展极限状态下20分钟内发生的蠕变程度。数据分为代表年轻人、中年人和老年人的三个年龄组类别。结果表明，伸展蠕变行为与先前报道的屈曲蠕变行为相似。老年腰椎的伸展蠕变范围似乎比年轻和中年组更大，但方差分析表明，年龄组之间蠕变的差异并不显著。脊柱韧带、关节突关节囊和椎间盘在伸展过程中的粘弹性行为足以产生特征性的蠕变 - 恢复曲线，但也许关节突关节在限制伸展中所起的重要作用足以防止随着年龄增长蠕变行为发生显著变化。相关性：本研究提供了腰椎对持续终末范围伸展负荷的生物力学反应信息。结果表明，在活体中，即使是短暂的持续伸展负荷期也可能导致显著的伸展蠕变。
