• Reliability of the incremental shuttle walk test and the Chester step test in cardiac rehabilitation

      Fallows, Stephen; Reardon, Melanie (University of Chester, 2008-09)
      Background: Cardiac Rehabilitation at Southport and Ormskirk NHS Trust has been in operation since 1998 and is carried out on two different sites. The latter has a very small exercise area and at this site the Chester Step Test (CST) is used to measure changes in exercise capacity after an eight week exercise programme and also to prescribe exercise for that patient. The former site has a much larger exercise area and historically has always used the incremental shuttle walk test (ISWT) for the same purpose. At both sites a practice test has not been routinely used to familiarise the patient with the test although anecdotally this seemed to show a difference in results. The results of performing a practice test would be analysed to look at the reliability. Objective: To evaluate the reliability of the Incremental Shuttle Walk Test (ISWT) and the Chester Step Test (CST). To compare results from the Incremental Shuttle Walk Test (ISWT) and the Chester Step Test (CST) as measures of change in exercise capacity in patients following an 8-week, hospital-based cardiac rehabilitation exercise programme. Setting: Gymnasia at Southport & Ormskirk NHS Trust. Methods: 33 subjects (26 males and 7 females, mean age 57.3) attended an 8-week cardiac rehabilitation exercise programme. All were assessed using ISWT and CST on three separate occasions: firstly at the patient assessment appointment prior to attendance at the programme, secondly on commencement of the programme (within one week of the first test) and thirdly during the final session of the programme. Both ISWT and CST tests were performed on the same day with a rest period of at least 20 minutes between them, to allow the heart rate to return to normal. The patients were taken to either 80% of their maximum heart rate or RPE 15. The ISWT distance walked in metres was measured. The CST measures predicted VO2max which was worked out by plotting the heart rates on the appropriate graph. Results: The results demonstrated the ISWT showed an element of learning, there was a difference between the practice test and that carried out on the first session of the cardiac rehabilitation exercise programme. The difference between the practice test and the final test carried out after the eight week programme was 125.2m, and between the baseline test and final test was 74.3m, there was therefore an increase of 50.9m within one week. The CST did not show the same element of learning and the results from the two tests carried out within one week did not show a significant difference. The results also showed that the ISWT and the CST showed no significant difference in the percentage increase of parameters measured between the two tests. ISWT showed mean improvement of 21.3% whilst CST showed a mean improvement of 24.7%. The O2 Pulse showed a difference between the two tests, it did not improve in the ISWT but did in the CST. Conclusion: The ISWT requires a practice test to familiarise the participant with the running of the test whereas the CST does not. The ISWT and CST, in this study, showed no significant difference between the two tests in percentage increase of meters (ISWT) and predicted VC>2max (CST) measured and could be used on the two different sites to show changes in exercise capacity. The Patients preferred the ISWT. Relevance to practice: The CST can be used where space and/or time are limited. A practice test at the assessment to attend the cardiac rehabilitation would be performed for the ISWT to familiarise the patients with the test but not for the CST.