Troy Karen L, Grabiner Mark D
Department of Movement Sciences (MC 994), University of Illinois at Chicago, 808 S. Wood, CME 690, Chicago, Illinois 60612, USA.
Exp Brain Res. 2005 Mar;161(3):343-50. doi: 10.1007/s00221-004-2078-8. Epub 2004 Oct 23.
Falling is a frequent cause of serious injury in older adults and trips are a dominant cause of falls in this rapidly growing population. Although there are few laboratory protocols that induce actual trips, there are many protocols that utilize surrogate tasks. These surrogate tasks, which are time-critical but do not involve an obstacle, appear to share a number of biomechanical characteristics with stepping responses following a trip. However, although rapid and safe negotiation of the obstacle and restoration of dynamic equilibrium are common requisites for success, we expected that stepping response kinematics during a successful recovery from a trip over a previously unseen obstacle would be substantially different than those of surrogate tasks without an obstacle. Unexpected trips were induced in 13 older men and women by an obstacle, the presence of which the subjects were previously unaware. Selected kinematics of the leading and trailing limb stepping responses during recovery from the induced trip were compared to those of two surrogate tasks that did not involve an obstacle. Multivariate analysis of variance (MANOVA) revealed that step height, step length, peak horizontal velocity, and peak vertical velocity of the leading and trailing limbs were significantly different during recovery from the induced trip compared to the surrogate tasks. These between-task performance differences may limit the extent to which performance of the surrogate tasks accurately and precisely reflect the potential to recover dynamic equilibrium following a trip. Therefore, these findings may be applicable in the design of new or modification of existing interventions to reduce falls in older adults.
跌倒是老年人严重受伤的常见原因，而绊倒在这一快速增长的人群中是跌倒的主要原因。虽然很少有实验室方案能诱发实际的绊倒情况，但有许多方案使用替代任务。这些替代任务对时间要求严格但不涉及障碍物，似乎与绊倒后的跨步反应具有一些生物力学特征。然而，尽管快速安全地越过障碍物并恢复动态平衡是成功的共同必要条件，但我们预计，在从未见过的障碍物上绊倒后成功恢复过程中的跨步反应运动学将与没有障碍物的替代任务有很大不同。13名老年男性和女性被一个他们之前未意识到存在的障碍物诱发意外绊倒。将诱发绊倒恢复过程中领先和落后肢体跨步反应的选定运动学与两个不涉及障碍物的替代任务的运动学进行比较。多变量方差分析（MANOVA）显示，与替代任务相比，诱发绊倒恢复过程中领先和落后肢体的步高、步长、水平峰值速度和垂直峰值速度有显著差异。这些任务间的表现差异可能会限制替代任务的表现准确精确反映绊倒后恢复动态平衡潜力的程度。因此，这些发现可能适用于设计新的或修改现有的干预措施以减少老年人跌倒。
