Ghent Gait Laboratory, University Hospital, 9000 Ghent, Belgium.
Gait Posture. 2010 Apr;31(4):537-9. doi: 10.1016/j.gaitpost.2010.01.024. Epub 2010 Mar 24.
Measurement of VO(2) based 'energy cost of walking' indices provide quantitative information that can be used clinically to ascertain progress and relative functional impairment in pathology. The accuracy and validity of these indices relies on being able to identify periods of steady state conditions, since it is only in steady state that there is a direct and predictable relationship between VO(2) consumption and energy expenditure. This paper presents a comparison of two new mathematically based approaches that have recently gained recognition as methods for identifying steady state during an energy cost assessment. The first applies a mathematically defined threshold for steady state within a (non-treadmill) walking trial. This method is compared with a statistically based approach that relies on the calculation of the correlation coefficient, Kendall's Tau to define steady state data. To examine the impact of both methods on the calculation of the energy cost of walking, each was applied to the calculation of two oxygen based energy cost of walking parameters, the non-dimensional net oxygen cost and the net oxygen cost with speed normalised to height in a cohort of unimpaired subjects and children with cerebral palsy. The results revealed that overall there were no clinically significant differences between the two methods. It is suggested that the methods can be used interchangeably to calculate the energy cost of walking.
基于 VO₂ 的“步行能量消耗”指标的测量提供了定量信息，可用于临床确定病理进展和相对功能障碍。这些指标的准确性和有效性依赖于能够识别稳定状态期，因为只有在稳定状态下，VO₂ 消耗和能量消耗之间才存在直接且可预测的关系。本文比较了两种新的基于数学的方法，这两种方法最近已被认可为在能量消耗评估期间识别稳定状态的方法。第一种方法在（非跑步机）步行试验中应用数学定义的稳定状态阈值。将该方法与基于统计学的方法进行了比较，该方法依赖于计算相关系数和 Kendall's Tau 来定义稳定状态数据。为了检查这两种方法对步行能量消耗计算的影响，将每种方法应用于两个基于氧气的步行能量消耗参数的计算，即无纲量净氧气消耗和标准化到身高的净氧气消耗，这些参数是在一组未受损受试者和脑瘫儿童中计算的。结果表明，两种方法之间总体没有临床显著差异。建议可以交替使用这些方法来计算步行能量消耗。
