Most patients find that recovering from surgery is difficult particularly after abdominal surgery for cancer or other intestinal disorders. The surgical stress, healing process and concerns if further treatments are required suggest that the post-operative period may not be the best time to get people to exercise to rehabilitate lost functions. Prehabilitation is the process of enhancing functional capacity of the individual to enable him or her to withstand an incoming stressor, such as surgery, and this study aims to evaluate the effectiveness of prehabilitation for colorectal surgery. Two groups will be formed by a random process and the prehabilitation group will use an exercise cycle and weights to build endurance and strength for a 3-week period prior to surgery. The other group will receive training about exercises that will help them move better after surgery. People who are malnourished prior to surgery will receive nutritional supplements. The results of this trial will be used to inform practitioners and patients alike of the benefits (or risks if any) of exercise in preparing for surgery.