Intersession reliability of center of pressure measurement during bipedal standing with different count-back orders

Abstract

Introduction: Dual-task assessments can identify changes in postural control during balance assessments. Static standing with backward counting is frequently used to evaluate postural control while dual-tasking. The most reliable countdown method for standing postural stability has not yet been defined. Research objective: to investigate postural stability's intra- and inter-day reliability while backward counting in different steps. Method: Thirty-nine healthy adults (20 females, 26.94 +/- 7.55 years) completed 70 s trials of stability tests with no dual-task, counting backward under five conditions (in ones, tows, threes, fours, and fives) while standing on a force-plate in three sessions: two sessions were on the same day, and the third session was one-week apart. The repeatability of measurements was tested using repeated-measure analysis of variance, interclass correlation, and standard error of measurements. Results: The interclass correlation scores ranged from 0.67 to 0.92, and the standard error of measurements ranged from 2.9 to 13.4. No significant systematic changes (p < 0.05) occurred between the testing sessions for any backward counting. Discussion: The backward counting showed higher reliability when performed in condition 5 (counting backward in five's). The inter-day reliability scores were greater than intera-day reliability. Conclusions: Dual-tasking with most backward counting (in ones to fives) is reliable, and a quantitative assessment of the center of pressure could be used to monitor the changes in postural stability between sessions.