Anderson Dennis E, Franck Christopher T, Madigan Michael L
Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, MA.
J Appl Biomech. 2014 Aug;30(4):542-6. doi: 10.1123/jab.2013-0275. Epub 2014 Jun 30.
The effects of gait speed and step length on the required coefficient of friction (COF) confound the investigation of age-related differences in required COF. The goals of this study were to investigate whether age differences in required COF during self-selected gait persist when experimentally-controlling speed and step length, and to determine the independent effects of speed and step length on required COF. Ten young and 10 older healthy adults performed gait trials under five gait conditions: self-selected, slow and fast speeds without controlling step length, and slow and fast speeds while controlling step length. During self-selected gait, older adults walked with shorter step lengths and exhibited a lower required COF. Older adults also exhibited a lower required COF when walking at a controlled speed without controlling step length. When both age groups walked with the same speed and step length, no age difference in required COF was found. Thus, speed and step length can have a large influence on studies investigating age-related differences in required COF. It was also found that speed and step length have independent and opposite effects on required COF, with step length having a strong positive effect on required COF, and speed having a weaker negative effect.
步速和步长对所需摩擦系数（COF）的影响混淆了对所需COF中年龄相关差异的研究。本研究的目的是调查在实验控制速度和步长时，自选步态期间所需COF的年龄差异是否持续存在，并确定速度和步长对所需COF的独立影响。10名年轻健康成年人和10名老年健康成年人在五种步态条件下进行步态试验：自选、不控制步长的慢速和快速，以及控制步长的慢速和快速。在自选步态期间，老年人步长较短，所需COF较低。在不控制步长的情况下以受控速度行走时，老年人所需COF也较低。当两个年龄组以相同的速度和步长行走时，未发现所需COF存在年龄差异。因此，速度和步长可能对研究所需COF中的年龄相关差异有很大影响。还发现速度和步长对所需COF有独立且相反的影响，步长对所需COF有强烈的正向影响，而速度有较弱的负向影响。
