Long-term maintenance of physical activity behaviour change post-intervention remains challenging. This study is investigating the feasibility of a behaviour change intervention based on Self-Determination Theory in people recovering from colorectal cancer and its effects on behaviour change 6 months post-intervention.

This study was a randomized controlled feasibility trial consisting of a 3-months active lifestyle intervention and a 3-months follow-up period. Participants were allocated to an active lifestyle programme (ALP) or the standard (SC) care group. ALP was offered 12 supervised exercise sessions over 3 months and six supportive behaviour change workshops. SC was encouraged to continue with their usual lifestyle. The intervention was informed by Self-Determination Theory.

The supervised exercise sessions took place in small groups of maximum 7 participants and lasted approximately 1 hour. Exercise included aerobic and resistance exercises. The behaviour change workshops were delivered in a motivational interviewing style, also in small groups of maximum 7 participants.

Participants were followed-up at 6 months. There was no contact with participants during the post-intervention and follow-up period.

Inclusion Criteria:

• a histologically confirmed diagnosis of colorectal cancer with Dukes stages A-C
• completed cancer treatment within the last 24 months,
• be able to understand spoken and written English
• score of 80 or more on the Karnofsky Performance Status Scale

Exclusion Criteria:

• already meeting general PA guidelines of 150 min of moderate PA or 75 min of vigorous intensity PA per week,
• recent myocardial infarction
• uncontrolled hypertension
• a pacemaker
• or unstable angina.