The influence of high-intensity compared with moderate-intensity exercise training on the health of colorectal cancer survivors: a randomised controlled trial

This project will investigate the feasibility and efficacy of high intensity exercise (HIE) as compared with moderate intensity exercise (MIE) on the insulin-like growth factor (IGF) axis, cardiorespiratory fitness, body composition and psychosocial health in colorectal cancer survivors. Study Design: This study is a three-arm, 12 week randomised controlled trial. Participants: Men and women who have been previously treated for colorectal cancer will be invited to participate in this randomised clinical trial. Intervention Structure: Following recruitment, participants will complete a familiarisation session, before which they will be provided with further details of the research program and afforded the opportunity to seek clarification for any questions related to the study. At the commencement of this session informed consent will be attained by way of a written consent form, witnessed by the principle investigator. The familiarisation session will conclude with a test of peak oxygen consumption (VO2peak test) After familiarisation, participants will complete a baseline testing session to measure all primary and secondary outcomes. Participants will then be randomised to one of three groups: (1) high intensity exercise - continuous (HIE-C) training group; (2) high intensity exercise - tapered (HIE-T) training group;(3) or a moderate intensity exercise (MIE) training group. The HIE-C and MIE groups will train at a frequency of 3 times per week for 8 weeks whereas the HIE-T group will train at a frequency of 3 times per week for the first 4 weeks, and at a frequency of once per week for the later 4 weeks. Participants will undergo testing at baseline (0 weeks), midpoint (4 weeks), endpoint (8 weeks) and follow-up (12 weeks). Participants will also be reassessed at further follow-up tests conducted at 6 and 12 months following the intervention. All exercise testing and training sessions will be supervised by an Accredited Exercise Physiologist (Exercise and Sports Science Australia). Participants will exercise in groups ranging from 1 to 4 depending on the suitability of times for each individual participant. Intervention: The HIE sessions will commence with 10 minutes of warm up at 50-70% of peak heart rate (HRpeak) before commencing 4 x 4 minute bouts of cycling at 85-95% HRpeak. Each 4 minute interval will be interspersed with a 3 minute period of active recovery at 50-70% HRpeak, totalling 38 minutes for the session. Attendance will be measured via a training log, and adherence to the prescribed exercise will be asssessed by continuous heart rate monitoring.