Measuring step kinematic variability on an instrumented treadmill: how many steps are enough?
Measuring step kinematic variability on an instrumented treadmill: how many steps are enough?
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DOI：
10.1016/s0021-9290(03)00108-8
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发表时间：
2003-08-01
影响因子：
2.4
通讯作者：
Grabiner, MD
中科院分区：
文献类型：
--
作者：
Owings, TM;Grabiner, MD
步态运动学的可变性与老年人跌倒有关。然而，在用于计算变异性的步骤数量方面，研究之间的差异在一个数量级上有所不同。如果用来计算可变性的步骤太少，就有可能出现统计上虚假的结果。另一方面，对于有运动障碍的受试者，需要太多步骤来估计变异性的协议给受试者施加了不必要的负担。我们已经确定了估计空间和时间步长运动学的可变性所需的最小步数。在仪表式跑步机上水平行走时，收集了700多步。准确估计步态的运动学可变性至少需要400步。由于步数太少，估计步数运动学变量的平均值和标准偏差的误差增大，这可能会增加统计设计方面的实验成本。这些结果在多大程度上可以转化为地面行走过程中收集的空间和时间步长运动学的可变性，有待进一步研究。(C)2003爱思唯尔科学有限公司。保留所有权利。
Variability of step kinematics has been associated with falls by older adults. However, between-study differences with regard to the number of steps used to compute variability have varied by an order of magnitude. If the number of steps used to compute variability is too low there is the potential for a statistically spurious outcome. On the other hand, for subjects with mobility impairments a protocol requiring too many steps to estimate variability imposes an unnecessary burden on the subjects. We have determined the minimum number of steps needed to estimate the variability of spatial and temporal step kinematics. More than 700 steps were collected during level walking on an instrumented treadmill. Accurate estimation of step kinematic variability required at least 400 steps. The increased error in estimating the mean and standard deviations of the step kinematic variables with too few steps can impose an experimental cost with regard to statistical design considerations. The extent to which translation of these results can be made to the variability of spatial and temporal step kinematics collected during over-ground walking awaits further research. (C) 2003 Elsevier Science Ltd. All rights reserved.