The VO2 Submax test uses treadmills to measure a client’s cardiorespiratory fitness and heart rate training zones at the Army Wellness Center on Joint Base Langley Eustis, Virginia. The AWC offers exercise testing for clients who are seeking to increase their speed and/or endurance. The test consists of three components: flexibility, muscular fitness and the VO2 Submax test. . (U.S. Air Force photo by Onyx Taylor-Catterson)