A Preliminary Validation of the 10-metre Incremental Shuttle Walk Test as a Measure of Aerobic Capacity in Women with Rheumatoid Arthritis

Abstract

Summary With the increasing importance of evidence-based practice and demonstrable clinical effectiveness, the need for valid outcome measures for all physiotherapy interventions is greater than ever. The VO2max remains the definitive measurement of aerobic capacity. However, there are serious practical and ethical concerns involved with applying such a demanding test to patients. As a consequence field tests are often applied with aerobic capacity inferred from performance. The most widely accepted and researched of these is the 10-metre incremental shuttle walk test (SWT) ( Singh et al., 1992 Singh SJ Morgan MD L Hardman AE et al. ‘Development of a shuttle walk test of disability in patients with chronic airflow limitation’. European Respiratory Journal. 1992; 7: 2016-2020 Google Scholar , Singh et al., 1994 Singh SJ Morgan MD L Hardman AE Rowe C Bardsley PA ‘Comparison of oxygen uptake during a conventional treadmill test and shuttle walking test in chronic airflow limitation’. European Respiratory Journal. 1994; 7: 2016-2020 PubMed Google Scholar ). In the present study the validity of a symptom-limited SWT as a measure of aerobic and functional capacity was examined with concurrent respiratory gas analysis. A VO2max value (aerobic capacity) established with linear extrapolation and observed VO2peak (functional capacity) were regressed against the number of shuttles completed. An earlier study ( MacSween, 2001 MacSween A (2001) ‘The reliability and validity of the strand nomogram and linear extrapolation for deriving VO2max from submaximal exercise data’. Journal of Sports Medicine and Physical Fitness, in press. Google Scholar ) established acceptable levels of reliability and validity of linear extrapolation. No statistically significant linear relationship was found between aerobic capacity and number of shuttles completed (R2 9.7%). Despite this finding, the advantages of developing an alternative to costly laboratory testing warrants further study of the SWT in patient groups. A statistically significant linear relationship was found between functional capacity and the number of shuttles completed (R2 61.4%). On the basis of the present results the SWT is a valid field test of functional capacity but not of aerobic capacity. With the increasing importance of evidence-based practice and demonstrable clinical effectiveness, the need for valid outcome measures for all physiotherapy interventions is greater than ever. The VO2max remains the definitive measurement of aerobic capacity. However, there are serious practical and ethical concerns involved with applying such a demanding test to patients. As a consequence field tests are often applied with aerobic capacity inferred from performance. The most widely accepted and researched of these is the 10-metre incremental shuttle walk test (SWT) ( Singh et al., 1992 Singh SJ Morgan MD L Hardman AE et al. ‘Development of a shuttle walk test of disability in patients with chronic airflow limitation’. European Respiratory Journal. 1992; 7: 2016-2020 Google Scholar , Singh et al., 1994 Singh SJ Morgan MD L Hardman AE Rowe C Bardsley PA ‘Comparison of oxygen uptake during a conventional treadmill test and shuttle walking test in chronic airflow limitation’. European Respiratory Journal. 1994; 7: 2016-2020 PubMed Google Scholar ). In the present study the validity of a symptom-limited SWT as a measure of aerobic and functional capacity was examined with concurrent respiratory gas analysis. A VO2max value (aerobic capacity) established with linear extrapolation and observed VO2peak (functional capacity) were regressed against the number of shuttles completed. An earlier study ( MacSween, 2001 MacSween A (2001) ‘The reliability and validity of the strand nomogram and linear extrapolation for deriving VO2max from submaximal exercise data’. Journal of Sports Medicine and Physical Fitness, in press. Google Scholar ) established acceptable levels of reliability and validity of linear extrapolation. No statistically significant linear relationship was found between aerobic capacity and number of shuttles completed (R2 9.7%). Despite this finding, the advantages of developing an alternative to costly laboratory testing warrants further study of the SWT in patient groups. A statistically significant linear relationship was found between functional capacity and the number of shuttles completed (R2 61.4%). On the basis of the present results the SWT is a valid field test of functional capacity but not of aerobic capacity.