Reliability and minimal detectable change of three functional tests: forward-lunge, step-up-over and sit-to-stand

[Purpose] To examine the intrasession and intersession reliability and the absolute reliability of three functional dynamic tests-forward-lunge, step-up-over and sit-to-stand tests-using computerized dynamic posturography. [Subjects and Methods] An intra-test and test-retest, repeated measure study was designed. Forty-five healthy subjects twice carried out the forward-lunge test, step-up-over test, and sit-to-stand test on two days, one week apart. The intrasession and intersession reliabilities as judged by the intraclass correlation coefficient (ICC) and the minimal detectable change of the three functional tests were calculated. [Results] Excellent to very good intrasession reliability of the forward-lunge test (ICC range of 0.9-0.8) was found. Very good to good intrasession reliability of the step-up-over test (ICC range of 0.9-0.5) was found and very good intrasession reliability of the sit-to-stand test (ICC range of 0.8-0.7) was found. The minimal detectable change at the 95% confidence level of most of the measures was lower than 30%. [Conclusion] The forward-lunge, step-up-over and sit-to-stand tests are reliable measurement tools.