Liu S H, Lawson D
Coastal Public Health Unit, Taree, New South Wales, Australia.
Aust J Sci Med Sport. 1995 Sep;27(3):62-7.
Power spectrum of the force moment generated from the fast Fourier transform (FFT) was utilised to evaluate standing balance on a force platform. The principles on generating and analysing an FFT spectrum from the output of the force platform are illustrated. Test-retest reliability of twelve healthy young people (age = 26 +/- 4 years) was performed with the preferred leg stance. The intraclass correlation coefficient (ICC), R, of mean power (P), spectral area (Sx) and maximum power (Px) were 0.89, 0.85 and 0.89 respectively, indicating that the spectral parameters are reliable quantitative measures of balance. Pearson product moment (PPM), r, of these spectral parameters were 0.95, 0.85 and 0.95 respectively showing that these spectral parameters are significantly correlated (p < 0.01). A comparison was made with respect to the one legged stance and two legged stance steadiness. The one legged stance (Sx = 95.75 cm.Hz) was significantly less stable than the two legged stance (Sx = 41.58 cm.Hz) with a value of 9.37. Moreover, the one legged stance was highly correlated to the two legged stance (r = 0.84), indicating that, in general, a subject who has a stable one legged stance should have a stable two legged stance.
利用快速傅里叶变换（FFT）生成的力矩功率谱来评估在测力平台上的站立平衡。阐述了从测力平台输出生成和分析FFT谱的原理。对12名健康年轻人（年龄 = 26 +/- 4岁）进行优势腿站立姿势的重测信度测试。平均功率（P）、频谱面积（Sx）和最大功率（Px）的组内相关系数（ICC）、R分别为0.89、0.85和0.89，表明这些频谱参数是可靠的平衡定量指标。这些频谱参数的皮尔逊积矩（PPM）、r分别为0.95、0.85和0.95，表明这些频谱参数显著相关（p < 0.01）。对单腿站立和双腿站立的稳定性进行了比较。单腿站立（Sx = 95.75 cm.Hz）明显比双腿站立（Sx = 41.58 cm.Hz）不稳定，差值为9.37。此外，单腿站立与双腿站立高度相关（r = 0.84），表明一般来说，单腿站立稳定的受试者双腿站立也应稳定。
