Long-term reliability of the incremental shuttle walking test in clinically stable cardiovascular disease patients

Abstract 

Objective

The incremental shuttle walking test (ISWT) is a valuable tool for assessing changes in patients’ functional capacity during cardiac rehabilitation. However, studies have only assessed its test–retest reliability in the short term. The purpose of this study was to examine long-term test–retest reliability of the ISWT in clinically stable cardiac patients.

Design

Test–retest reliability assessment.

Setting

Continuous, community-based phase IV cardiac rehabilitation centre.

Participants

Thirty patients with cardiovascular disease (15 males, 15 females; age 55 to 80 years) volunteered to participate in the study.

Interventions

Participants undertook two ISWTs, a minimum of 8 weeks apart.

Main outcome measures

ISWT performance in metres.

Results

Overall, the mean distance walked in the pre-test was 502±161m and this did not differ from test to retest. The intraclass correlation coefficient was 0.80, indicating good test–retest reliability. Using the Bland and Altman method, there was a small mean test–retest difference (−7m). The 95% limits of agreement were large, ranging from −203m to 189m.

Conclusions

Over long test–retest durations, there appears to be no learning effect in the ISWT, negating the need for a practice walk. The long-term random variation in the ISWT test is larger than in previous studies, probably due to greater physiological and psychological variation in the participants over 8 weeks compared with that seen in day-to-day testing. Factors influencing long-term test–retest reliability of the ISWT require further elucidation.

Keywords: Incremental shuttle walking test, Exercise test, Long-term test–retest reliability, Cardiovascular disease, Cardiac rehabilitation