Stages of exercise behaviour change: a pilot study of measurement validity

Abstract

Objectives: The Stage of Exercise Behaviour Change (SEBC) scale is used to monitor physical activity levels and change in a variety of contexts. However, there is insufficient conceptual discussion relating to its use and a lack of objective evidence for its validity. Pilot work was undertaken to explore the issues involved in validating a SEBC scale using objective monitoring of exercise behaviour, and subsequent discussion aims to inform future validity studies. Design: Estimates of of physical activity energy expenditure (kilocalories) were calculated for 20 participants, while minutes spent in moderate and vigorous activity were extrapolated from heart rate data in 23 participants. The SEBC scale was completed after a three-day objective monitoring period. Data were compared descriptively and using analysis of variance. Results: Inter-stage differences in objective measurements of energy expenditure and minutes of vigorous activity participation provided hierarchical confirmation of the SEBC scale. Conclusions: Objectively monitored exercise partcipation supported previous work in its confirmation of the Stage of Change hierarchy. However, in order to build confidence in the tool, it will be necessary to explore minutes of exercise participation over a six-month period. This would enable comparison of objectively monitored activity levels against the threshold level of exercise described as the target behaviour. Suggestions are made as to how this could be carried out. A word of caution is provided in relation to current use of SEBC tools in measurement contexts.