Connelly D M, Thomas B K, Cliffe S J, Perry W M, Smith R E
School of Physical Therapy, The University of Western Ontario, London, Ontario, Canada.
Physiother Can. 2009 Spring;61(2):78-87. doi: 10.3138/physio.61.2.78. Epub 2009 May 12.
This study's purposes were to examine the measurement properties of the 2-minute walk test (2MWT), to illustrate the use of reliability coefficients in clinical practice, and to estimate sample size for a subsequent validity study.
Sixteen residents of long-term care (LTC; mean age = 87 years) completed two 2MWTs with Rater A and two 2MWTs with Rater B on test days 1 and 2, approximately 1 week apart. On a third test day, subjects completed one trial of the Berg Balance Scale (BBS), timed up-and-go (TUG) test, and 6-minute walk test (6MWT) with Rater A. On 2 other test days, approximately 1 week apart, Rater A administered the 2MWT to five older adults living in a retirement facility. Absolute and relative reliability and concurrent and known-groups validity coefficients were calculated.
No main effect for rater, trial, or occasion was found. Test-retest reliability estimates of 0.94 and 0.95 were obtained. The 2MWT demonstrated concurrent validity (r > or = 0.84) with the BBS, TUG, and 6MWT. Comparison of distance walked by LTC and retirement residents showed a difference of 72.9 m (95% CI: 44.2, 101.6). The results suggest that 90% of truly stable older adults will display random fluctuations in 2MWT performance within a boundary of 15 m.
The 2MWT had sound measurement properties in this sample of LTC residents. Based on our results, 24 subjects would be required for a subsequent hypothesis-testing validity study.
本研究旨在检验2分钟步行试验（2MWT）的测量特性，阐述可靠性系数在临床实践中的应用，并为后续的效度研究估计样本量。
16名长期护理（LTC）机构居民（平均年龄 = 87岁）在第1天和第2天（间隔约1周）分别由评估者A完成两次2MWT，由评估者B完成两次2MWT。在第三个测试日，受试者由评估者A完成一次伯格平衡量表（BBS）测试、计时起立行走（TUG）测试和6分钟步行试验（6MWT）。在另外两个间隔约1周的测试日，评估者A对居住在退休社区的5名老年人进行2MWT测试。计算绝对和相对可靠性以及同时效度和已知群组效度系数。
未发现评估者、试验或测试时间的主效应。重测信度估计值分别为0.94和0.95。2MWT与BBS、TUG和6MWT显示出同时效度（r≥0.84）。LTC机构居民和退休社区居民步行距离的比较显示差异为72.9米（95%CI：44.2，101.6）。结果表明，90%真正稳定的老年人在2MWT表现中的随机波动将在15米范围内。
对于LTC机构居民样本，2MWT具有良好的测量特性。根据我们的结果，后续假设检验效度研究需要24名受试者。
