DEVELOPMENT OF AN INSTRUMENT TO MEASURE THE „QUASI-STATIC“ SENCE OF BALANCE

Abstract

INTRODUCTION: A measuring instrument was developed to record oscillations with regard to the projection of the center of gravity of the body (on an axis to the position where the subject stands). The measuring instrument works like a seesaw. The axis runs along the standing position. Variations are recorded by two linear positional sensors placed under the construction. The standing surface can be rotated up to 5.6°, and additionally, swaying is dampened by springs. METHODS: In the study the above-mentioned construction was compared with the Kistler force platform, with which the body’s center of gravity is projected onto the base ground. Nineteen subjects took part in the study, which required them to stand on one foot for 40 seconds with closed eyes; each subject repeated this five times, each time trying to maintain his balance. The test was repeated one week later. Different features of both measuring instruments were compared. These were among other things the mean variation of measurements, the average of the mean, the length of the curve of the projection and the greatest divergence from the mean. RESULTS: As a result it can be stated that each feature states a different aspect of the motor quality ‘quasi-static balance’. The degree of definiteness among features of one measuring instrument differed between 2% and 95%. A significant correlation between the features of both measuring instruments was detectable in a significant way for two features. Retest reliability could be detected for almost all features with high significance (p < .01). Quality criteria were fulfilled, in the sense of classical test theory, i.e., reliability, validity and objectivity. Furthermore, the measuring system weighs only 5 kg and is thus easy to transport. CONCLUSIONS: This study shows that the developed measuring instrument is suitable as an alternative measuring system to the Kistler force platform in the measuring of quasi-static balance on one axis. REFERENCES: Bös, K. (1987). Handbuch sportmotorischer Tests. Göttingen: Dr. C. J. Hogrefe. Fetz, F. (1994). Sensomotorisches Gleichgewicht im Sport. Vienna: Österreichischer Bundesverlag.