The incremental shuttle walking test (ISWT) is widely used to assess patients with chronic obstructive pulmonary disease. We hypothesised that it would be an appropriate tool to assess patients with coronary heart disease following coronary artery bypass grafts. We therefore explored the reproducibility, validity and sensitivity of the ISWT following rehabilitation.
Participants completed three ISWTs and an incremental treadmill test over 7 days. Eleven patients repeated the ISWT following rehabilitation.
Cardiac rehabilitation department.
Thirty-nine patients, 34 of whom were male, with a mean age of 61.2 years (S.D. 8.5), 6–8 weeks after coronary artery bypass graft surgery.
Main outcome measures
Maximum oxygen uptake (O2peak, ml/min/kg) and ISWT.
Mean (S.D.) distances for the three ISWTs were 448m (137.8), 487m (147.6) and 481m (138.2). There was no statistically significant difference between the three ISWTs. The mean difference between Tests 1 and 2 was 42.8m (95% confidence interval 59.1–26.5m) compared with 1.7m (95% confidence interval −1.86–5.29) between Tests 2 and 3. The mean O2peak was 21.0 (S.D. 4.5) ml/min/kg. There was a significant relationship between the results for the three ISWTs and O2peak (r=0.79, r=0.86 and r=0.87 for Tests 1–3, respectively). Following rehabilitation, there was a significant increase in the distance walked; the mean difference between the second ISWT and the post-rehabilitation ISWT was 81.8m (95% confidence interval 53.2–110.4, P<0.001).
The ISWT correlates well with O2peak and is a reliable measure of cardiorespiratory fitness in this population after one practice walk.
Reproducibility and validity of the incremental shuttle walking test in patients following coronary artery bypass surgery
S.J. Fowler, S.J. Singh, S. Revill
Physiotherapy - March 2005 (Vol. 91, Issue 1, Pages 22-27, DOI: 10.1016/j.physio.2004.08.009)