The feasibility of segmental method in testing human balance control with a three dimensional motion analysis system / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the reliability and sensitivity of a three dimensional motion analysis system by using the segmental method.Methods Ten healthy young men participated in this study.They were asked to stand with one leg and with their eyes open and closed,respectively,each lasted for 30 seconds and was re- peated twice.According to the 12-segment rigid body model of the human body,twenty-one infrared light emitting di- ode(1RED)markers were placed over the bony prominences on the proximal and distal ends of each segment,the motion track of the IRED markers was recorded by the three dimensional motion analysis system.The mean sway am- plitude( MSA )and the sway path(SP)of the center of gravity(COG)were calculated.Correlation analysis was used to determine the reliability between the two repetitions.Paired sample t-test was used to determine the sensitivity be- tween the eyes open and closed conditions.Results The correlation coefficients of the MSA of the COG in the eyes open and closed conditions were 0.623 and 0.018,respectively,and the correlation coefficients of the SP of the COG were 0.936 and 0.654,respectively.It was also shown that significant differences existed among the three directions of the MSA of the COG and the SP of the COG.Conclusion Besides the weak reliability of the MSA of COG in the eyes closed condition,the high reliability and sensitivity of the MSA and SP of the COG are found.The segmental method can be used in the scientific study of human balance control.