This study will be a randomized trial comparing the use of only water or water and air insufflation during colonoscopy insertion by trainees. This study will be looking at the impact that water-assisted colonoscopy has on resident learning. The investigators hypothesize that the use of water only compared to water and air will improve the learning experience for trainees.

In this trial, the investigators will offer participation in the study when patients present for their scheduled routine colonoscopy. The participants will be asked to give consent for the colonoscopy procedure and participation in the trial. After consent is obtained and information is taken from the participants, each participant would be randomly assigned to either water only or water and air insufflation on insertion via a computer-generated random number. All patients over the age of 18 presenting for their scheduled colonoscopy at either the Health Sciences Centre or St. Clare's Mercy Hospital in St. John's, Newfoundland, can participate in the study. The colonoscopy will then be done in the usual manner with appropriate sedation. Patients will then be debriefed regarding their colonoscopy following the procedure in recovery. At the completion of the data extraction above, all trainee participants will undergo a semi-structured exit interview with one of the study investigators.

Inclusion Criteria:

• All patients over the age of 18 presenting for their scheduled routine colonoscopy at either the Health Sciences Center or St. Clare's Mercy Hospital in St. John's, NL, can participate in the study.

Exclusion Criteria:

• Previous bowel resection, refusal to participate, inability to provide informed consent, known bowel obstruction, emergency colonoscopy. It will be noted if patients have had a previous hysterectomy, patient's age, BMI, gender, and quality of bowel preparation as these factors have been known to prolong cecal intubation.

The participant will be blinded to the intervention until after the pain score has been completed.