심선미1, 오덕원2

1유성유웰니스병원 물리치료실, 2대전대학교 보건스포츠과학대학 물리치료학과

Background: This study aimed to investigate the practice effect of the 6-minute walk test (6MWT) after providing
the subjects with knowledge of the results (KR).
Methods: Sixteen subjects with post-stroke hemiparesis volunteered to participate in this study. The 6MWT was
performed by having the subjects take repeated walks along a 20-m walkway for 6 minutes; and the maximum
distance walked was recorded. Two trials of the 6MWT were conducted under three conditions: no-KR, immediate-
KR (providing knowledge of the time taken to complete each 20-m distance), and summary-KR (providing
knowledge of the time taken to complete 60 m).
Results: The practice effects of all 3 conditions were determined by using the paired t-test, intraclass correlation
coefficient (ICC) with <0.75, and the Bland-Altman plot. The findings of the paired t-test showed a significant difference
under the immediate-KR condition only; however, no significant differences were noted under the
no-KR and summary-KR conditions. In a data agreement analysis across the two trials using the ICC, none of
the obtained values under the three conditions were in an acceptable range indicative of a practice effect. In the
Bland-Altman plot, a greater data variation was observed under the immediate-KR condition than under the
other two conditions. When comparing the conditions, the immediate-KR condition differed significantly from
the no-KR condition.
Conclusions: Our findings do not support the presence of a practice effect across the 6MWT. However, a practice
effect seems to be clinically possible when the immediate-KR condition is incorporated into this test.

Korean J Health Promot 2011;11(1):42-47
Keywords: 6-minute walk test, Knowledge of result, Practice effect, Hemiparesis,