The 6MWT: will different methods of instruction and measurement affect performance of healthy aging and older adults?

The Six-Minute Walk Test (6MWT) is commonly used to assess the fitness level of healthy adults and of older adults with disabilities. It can also be used as an intervention to increase walking endurance. However, its use may be limited in certain rehabilitation settings due to space requirements. If it can be shown that the measured linear distance walked in the 6-minute walk is comparable to the distance walked as measured by a pedometer, the test may be more widely used in a variety of rehabilitation settings. In addition, questions exist as to whether the method of instruction ("walk as far as you can" vs "walk as fast as you can") can impact the rate of perceived exertion of the person performing the test. The purposes of this study were to assess for differences in the measured linear distance and from the gender-based predicted value when compared to the pedometer measurement. In addition, we assessed the difference, if any, in the rate of perceived exertion (RPE) using the 2 different methods of administration. Furthermore, the distance in meters walked using the 2 different methods of instruction was compared; likewise, comparisons were made of these values to predicted values.

A group of 26 older adults participated in this descriptive study. After a practice trial, each person completed 2 linear trials using different methods of instruction, ("walk as fast as you can" or "walk as far as you can") of the 6MWT while wearing a DIGI-WALKER SW-651 pedometer. Vital signs were taken before and after each trial. Linear distance, pedometer distance, and numeric value RPE were recorded.

Paired t tests demonstrated no gender differences. An intraclass correlation coefficient (2,1) of 0.822 was calculated between all dependent variables. A repeated measures MANOVA was conducted to assess for differences between all variables resulting in no differences (F = 1.98; P = .13). Pairwise comparisons were also insignificant for the distance measurements except predicted value and pedometer fast P = .024. Paired t tests also demonstrated differences between RPE between trials (t = 2.15; P = .041).

There was good agreement between these distance measures for the 6MWT. The use of a pedometer was found to be a valid measure of walking distance during the 6MWT. It was also found that the method of instruction made no differences in walking distance. Although the change was minimal on the Borg scale, the RPE was found to be significantly different between far and fast trials in healthy adults. From this study, it appears that that either mode of instruction is valid in healthy community-dwelling populations. Future studies should include populations with impairments.