Effect of compensation procedures for velocity on repeatability and variability of gait parameters in normal subjects.
OBJECTIVE To evaluate the effects of a mathematical procedure that adjusts for gait velocity on the variability seen in gait analysis.


METHODS
Evaluation before and after compensation.


METHODS
Gait laboratory, Fukui University Hospital, Japan.


METHODS
Fourteen normal volunteers.


METHODS
A computerized gait analysis system with two forceplates and a light source spot measuring device was used. Gait measurement in each subject was performed on three different days.


RESULTS
The gait parameters measured on three different days were significantly different, particularly step length, stride length, velocity, the components of floor-reaction forces and hip motion. In these parameters, intraclass correlation coefficient, ICC (1,1) was not high (range 0.05-0.71). However, there was a high correlation between these parameters and velocity and high repeatability was obtained following compensation for velocity (ICC (1,1), range 0.73-0.97). In contrast, compensation of parameters whose measurement was not significantly different before compensation did not improve ICC (1,1). Variability of all parameters was acceptable, however CV (an index of variability) improved significantly after compensation compared with that before compensation in six of 15 parameters.


CONCLUSIONS
Our findings suggest that low repeatability in gait parameters should be considered even when the gait of normal subjects is measured on different days. A high repeatability and more acceptable variability were obtained when the data were compensated for velocity.
Shimada
Seiichiro
S
Division of Physical Therapy and Rehabilitation Medicine, Fukui University Hospital, Japan. sshima@fmsrsa.fukui-med.ac.jp
Kobayashi
Shigeru
S
Wada
Makoto
M
Sasaki
Shinichi
S
Kawahara
Hideo
H
Uchida
Kenzo
K
Yayama
Takafumi
T
Baba
Hisatoshi
H
D000704:Analysis of Variance; D005684:Gait / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D012044:Regression Analysis; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted