Abstract: ObjectiveTo assess a simple apparatus measuring displacement of pelvis in clinical application.MethodsTwo testers measured the displacement of pelvis of 20 healthy young subjects moving their body forward, backward, leftward and rightward in standing position. The reliability of inter- and intra-tester was tested with intraclass correlation co-efficiency (ICC). And the validity between this method and Functional Reach Test (FRT) was tested.ResultsThe ICC of inter- and intra-tester were 0.91～0.97 and 0.94～0.98 respectively, and correlated with FRT (r=0.88, P<0.01).ConclusionThis simple apparatus can be used in a balance test.

Key words: simple apparatus, displacement of pelvis, reliability, validity