Testing walking performance in patients with low back pain: will two minutes do instead of six minutes?

Abstract

Purpose The six-minute walk test (6MWT) can assess walking function but is time-consuming. We investigate the correlation of performance over the first two minutes of the 6MWT (2MWT#) and the 6MWT. We also evaluate the 2MWT#’s ability to predict 6MWT results, assess correlations to secondary explanatory outcomes, and assess the ability to discriminate between clinical subgroups. Material and methods A cross-sectional study of 124 participants with LBP. Correlations between the 2MWT# and 6MWT and secondary outcomes were evaluated using the Pearson product-moment correlation coefficient. The predictive ability of the 2MWT# was defined as the residual distance between the observed 6MWT and three times the 2MWT#. Differences between clinical subgroups were evaluated using the Wilcoxon rank test. Results The 2MWT# and 6MWT correlated highly (r = 83, 95% CI 0.76 − 0.87). The 2MWT# overestimated 6MWT results with 46.8 meters (SD 67.0). Both tests correlated with secondary outcomes and discriminated similarly between clinical subgroups. Conclusions: The 2MWT# correlates highly with 6MWT but overestimates the observed 6MWT by 9%. Because it is shorter, possibly less burdensome, and with little or no loss of discriminatory ability, we consider it a legitimate alternative to the 6MWT in patients with LBP. Implications for rehabilitation Walking function is often affected in patients with low back pain (LBP). The six-minute walk test (6MWT) is frequently used to assess walking function but is time-consuming. A shorter two-minute walk test is a legitimate alternative in patients with LBP as it correlates highly with the 6MWT and has little or no loss of discriminatory ability between clinical subgroups.