The X-iser Core 4™ (XC4) is a unique program using four exercises that incorporate the entire body, particularly the "core" muscles (i.e., stomach, hips, and low back).  Each exercise is completed to fatigue or for 60 seconds — the total workout time is four minutes or less.  While producing significant results with a minimal investment of time, this Program is excellent for the busy individual.  The recovery times between exercises may be varied to suit one’s needs.  For example, rest times of one hour will not induce perspiration and, therefore, fit well into a work day at the office.  There are different levels of difficulty and the program is progressive and sophisticated enough to accommodate beginners as well as the requirements of an Olympic or professional-level athlete in any sport.  Complete 2-3 sessions per week in addition to the Short Burst Exercise Program™.