Walking for the assessment of balance in healthy subjects older than 40 years.

BACKGROUND

The Berg scale and the timed 'up and go' test (TUG) are established measures to assess mobility in frail older adults. As an alternative to self-paced tests to assess aerobic exercise capacity, the incremental shuttle walk test (ISWT) was developed. We hypothesized that ISWT may be useful for the assessment of aerobic capacity and balance simultaneously in healthy adults.

OBJECTIVES

There are 3 objectives: (1) to evaluate the intra-tester reliability of TUG in healthy subjects; (2) to compare the validity of TUG, ISWT and comfortable gait speed (GS) to evaluate balance assessed by the Berg balance scale, and (3) to evaluate the correlations among these walking tests.

METHODS

We studied a sample of 64 subjects (82.81% women) aged 40-84 years to assess the intra-tester reliability of TUG. Of these, 21 subjects also performed ISWT, GS and the Berg balance scale. We also assessed height, weight, body mass index, spirometry and reported physical activity.

RESULTS

The average time to complete TUG was 7.23+/-1.27 s. The interclass correlation coefficient of TUG was excellent (0.936; 95% CI: 0.895-0.961). Age (r=0.36), GS (r=-0.64), GS/height (r=-0.44), ISWT (r=-0.65) and the Berg score (r=-0.65) were correlated with TUG (p<0.05). The Berg score was significantly (p<0.05) correlated with GS (r=0.61) and ISWT (r=0.61). Moreover, ISWT was mutually related with GS (r=0.68). We evaluated 2 models of linear regression, using GS and TUG as independent variables in each of them. In the 1st model, GS described 47% of the ISWT variability. In the 2nd, TUG described 42.7% of the ISWT variability.

CONCLUSIONS

The capacity of walking is related to balance in healthy adults and seniors. Our results suggest the usefulness of ISWT as a new tool for the simultaneous evaluation of the aerobic capacity and balance in healthy subjects. An important part of the ISWT variation was explained by GS and TUG. Secondly, we confirmed the significant influence of age in the TUG performance and the excellent reliability of this field walking test.