A criterion measure of walking capacity in lumbar spinal stenosis and its comparison with a treadmill protocol

Measurement (validity) study.

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.

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.

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.

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.

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).