Field exercise tests used to measure physical fitness and functional capacity in cardiac rehabilitation

Submission note: A thesis submitted in total fulfilment of the requirements for the degree of Doctor of Philosophy to the Department of Rehabilitation, Nutrition and Sport, School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora.

Thesis with publications.

The aim of this thesis was to determine the best field exercise test for use in cardiac rehabilitation for the measurement of physical fitness and functional capacity. To do this, the studies and methods followed the framework for assessing measurement properties proposed by the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) group. The most common field tests used in cardiac rehabilitation were the six-minute walk test (6MWT) and the 10 m incremental shuttle walk test (10 m ISWT). A series of three empirical studies with a total of 107 participants and a systematic review were completed. In a population of patients commencing cardiac rehabilitation, the 6MWT demonstrated a high level of systematic error and insufficient retest reliability when up to three tests were performed. The 10 m ISWT was highly reliable when both relative reliability and measurement error were assessed for both consistency and absolute agreement. Evidence supported validity for the 10 m ISWT when compared with other measures of function and the criterion, the symptom-limited exercise test. The 10 m ISWT was responsive to change over an eight-week cardiac rehabilitation program. The test showed acceptable interpretability, the minimal important change across a cardiac rehabilitation program was greater than the smallest detectable change. Support for the measurement properties and interpretability did not change when one or two tests were performed. Results were consistent with the systematic review (n equals 78 studies), which synthesised measurement properties of field exercise tests in cardiac rehabilitation. In conclusion, the 10 m ISWT was found to be the preferred field test for measurement of physical fitness and functional capacity in cardiac rehabilitation, with acceptable measurement properties when a single test is performed. A single test is suitable for ambulant low-intermediate risk patients entering low to moderate intensity cardiac rehabilitation programs.

This thesis was a recipient of the Nancy Millis Award for theses of exceptional merit.