Rationale: While total knee replacements (TKA) are one of the most commonly performed surgical procedures in the United States, this procedure can also be very painful. Postoperative mobilization and rehabilitation is vital to a patient's recovery, but inadequate pain control can impede patients' progress. Diaphragmatic breathing is an additional non-pharmacological and non-invasive tool with no adverse effects that could aid in recovery. This will serve as a pilot study for a possible larger controlled trials.