To support health-related behaviour changes, consumers may use technologies such as smartphones, smartbands, sensors and other devices connected to the Internet of Things. Research has shown that personalising the interaction, including the interface, data, and feedback, can result in more effective outcomes in terms of the desired changes in behaviour. This paper reports on a pilot study that tested a smartphone step challenge application that was personalised based on the user’s motivational style using the Behavioural Inhibition System/Behavioural Approach System (BIS/BAS) scales of Reinforcement Sensitivity Theory. The results indicated that participation in the step challenge did change the behaviour of the participants. For half the days of the challenge, the application delivered pep talks tailored to the two motivational styles and to the participant’s behaviour (taking more or fewer steps than on the previous day). While the study found that participants with different motivational styles responded differently to the motivational cues (pep talks), their responses did not appear to be influenced by the personalisation of the pep talks.