Study Design. Measurement (validity) study.
Objective. To develop and examine reproducibility of a criterion measure of walking capacity for use with lumbar spinal stenosis (LSS) patients, and use this criterion to examine the validity of a treadmill test for the same purpose.
Summary of Background Data. To date, there is no criterion measure of walking capacity advocated for use with LSS populations. Treadmill tests of walking have become more common in LSS literature and research, yet there is insufficient evidence to support the use of these tests as valid outcome measures. Therefore, our aim was to develop a criterion measure and to examine the validity of a treadmill protocol for the measurement of walking capacity in LSS.
Methods. A criterion measure of walking capacity in LSS, the self-paced walking test (SPWT) was developed and its test-retest reproducibility examined. Validity of a treadmill test was then examined using the criterion measure for comparison.
Results. The SPWT was found to be highly reproducible with a test-retest intraclass correlation coefficient of 0.98 for total distance walked, in a sample of subjects diagnosed with LSS (n = 33). Although the treadmill test was found to be highly correlated with the SPWT (r = 0.88), 89% of 45 subjects walked further during the SPWT than on the treadmill. Mean walking distances for the SPWT and treadmill test were 987.3 ± 913.9 m and 611.3 ± 666.0 m respectively, resulting in a significant difference (P < 0.05) between SPWT and treadmill tests.
Conclusion. The SPWT is presented as a feasible and reproducible criterion measure of walking capacity for use with LSS patients. Although a strong relationship was demonstrated between the treadmill protocol and the SPWT, a systematic bias was observed with patients walking significantly further in the SPWT (36% in mean).
This study presents a valid and reproducible criterion measure of walking capacity for use with lumbar spinal stenosis patients, the self-paced walking test. This test was used to examine the validity of a treadmill test, and it was found that treadmill testing significantly underestimates walking capacity in this population.
From the University of Alberta, Edmonton, Alberta, Canada.
Acknowledgment date: January 25, 2009. Revision date: March 23, 2009. Acceptance date: March 25, 2009.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Institutional funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Supported by the EFF Support for the Advancement of Scholarship, University of Alberta. Also, by the Alberta Heritage Foundation for Medical Research and the Alberta Provincial CIHR Training Program in Bone and Joint Health (to C.C.T.) and by the Canada Research Chairs Program (to M.C.B.).
Approval for involvement of human subjects was obtained through the Health Research Ethics Board at the University of Alberta.
Address correspondence and reprint requests to Christy C. Tomkins, PhD, 3–48 Corbett Hall, University of Alberta, Edmonton, Alberta, Canada, T6G 2G4; E-mail: firstname.lastname@example.org.