Health and Safety The Bruce Protocol Treadmill Test for Athletes A Fitness Evaluation Used to Measure VO2 Max By Elizabeth Quinn Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics. Learn about our editorial process Elizabeth Quinn Reviewed by Reviewed by John Honerkamp on August 20, 2020 twitter linkedin instagram John Honerkamp is an RRCA and USATF certified running coach, celebrity marathon pacer, and recognized leader in the New York City running community. Learn about our Review Board John Honerkamp on August 20, 2020 Print Dan Kitwood / Staff / Getty Images Table of Contents View All VO2 Max Testing How the Bruce Treadmill Test Works Bruce Protocol Norms Bruce Treadmill Test Cautions The Bruce protocol treadmill test is used to estimate the overall fitness of endurance athletes. The test was originally designed by cardiologist Robert A. Bruce in 1963 as a non-invasive test to assess patients with suspected heart disease. In a clinical setting, the Bruce treadmill test protocol is sometimes called a stress test or exercise tolerance test. The test can be used to estimate maximal oxygen uptake (VO2 max), which is a measure of an athlete's capacity to perform sustained exercise. It is linked to aerobic endurance. VO2 Max Testing Maximal oxygen uptake (VO2 max) specifically refers to the maximum amount of oxygen that an individual can take in and use during intense or maximal exercise. It is measured as milliliters of oxygen used in one minute per kilogram of body weight (ml/kg/min). The Bruce treadmill test is an indirect test. It estimates VO2 max using a formula and an athlete's performance on a treadmill as the workload is increased. Other methods of measuring VO2 max are more cumbersome and require the direct collection and measurement of the oxygen volume and oxygen concentration of inhaled and exhaled air the athlete uses while running. Direct testing requires far more elaborate and sophisticated equipment and data collection than the formula based on time on the treadmill. How the Bruce Treadmill Test Works The Bruce protocol is a maximal exercise test where the athlete works to complete exhaustion as the treadmill speed and incline is increased every three minutes. The length of time on the treadmill is the test score and can be used to estimate the VO2 max value. During the test, heart rate, blood pressure, and ratings of perceived exertion are often also collected. Bruce Treadmill Test Stages Stage 1: 1.7 mph at 10 percent gradeStage 2: 2.5 mph at 12 percent gradeStage 3: 3.4 mph at 14 percent gradeStage 4: 4.2 mph at 16 percent gradeStage 5: 5.0 mph at 18 percent gradeStage 6: 5.5 mph at 20 percent gradeStage 7: 6.0 mph at 22 percent grade Bruce Protocol Formula for Estimating VO2 Max These are the formulas used. T stands for total time on the treadmill, measured as a fraction of a minute (a test time of 9 minutes 30 seconds would be written as T=9.5). For men: VO2 max = 14.8 - (1.379 x T) + (0.451 x T²) - (0.012 x T³)For women: VO2 max = 4.38 x T - 3.9 Bruce Protocol Norms VO2 Max Norms for Men as Measured in ml/kg/min Age Very Poor Poor Fair Good Excellent Superior 13-19 <35.0 35.0-38.3 38.4-45.1 45.2-50.9 51.0-55.9 >55.9 20-29 <33.0 33.0-36.4 36.5-42.4 42.5-46.4 46.5-52.4 >52.4 30-39 <31.5 31.5-35.4 35.5-40.9 41.0-44.9 45.0-49.4 >49.4 40-49 <30.2 30.2-33.5 33.6-38.9 39.0-43.7 43.8-48.0 >48.0 50-59 <26.1 26.1-30.9 31.0-35.7 35.8-40.9 41.0-45.3 >45.3 60+ <20.5 20.5-26.0 26.1-32.2 32.3-36.4 36.5-44.2 >44.2 VO2 Max Norms for Women as Measured in ml/kg/min Age Very Poor Poor Fair Good Excellent Superior 13-19 <25.0 25.0-30.9 31.0-34.9 35.0-38.9 39.0-41.9 >41.9 20-29 <23.6 23.6-28.9 29.0-32.9 33.0-36.9 37.0-41.0 >41.0 30-39 <22.8 22.8-26.9 27.0-31.4 31.5-35.6 35.7-40.0 >40.0 40-49 <21.0 21.0-24.4 24.5-28.9 29.0-32.8 32.9-36.9 >36.9 50-59 <20.2 20.2-22.7 22.8-26.9 27.0-31.4 31.5-35.7 >35.7 60+ <17.5 17.5-20.1 20.2-24.4 24.5-30.2 30.3-31.4 >31.4 Bruce Treadmill Test Cautions Because the Bruce treadmill test is a maximal exercise tolerance test, it requires a physician's clearance and expert supervision. In an untrained individual or an athlete with an underlying heart condition, exercising to a maximal effort can lead to injury or heart events. While performing the test, clinicians monitor the patient's vital signs continuously and stop the test at any sign of trouble. If you take this test, be sure that your testing facilitator has the appropriate clinical expertise and has conducted such tests many times before you step on the treadmill. Cooper Test: A 12-Minute Run to Check Aerobic Fitness Was this page helpful? Thanks for your feedback! Get exercise tips to make your workouts less work and more fun. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Luong MW, Ignaszewski M, Taylor CM. Stress testing: a contribution from Dr. Robert A. Bruce, father of exercise physiology. B C Med J. 2016;58(2):70-76. Strzelczyk TA, Cusick DA, Pfeifer PB, Bondmass MD, Quigg RJ. Value of the Bruce protocol to determine peak exercise oxygen consumption in patients evaluated for cardiac transplantation. Am Heart J. 2001;142(3):466-75. doi:10.1067/mhj.2001.117508 University of Virginia School of Medicine. VO2 max testing. Fletcher GF, Ades PA, Kligfield P, et al. Exercise standards for testing and training: A scientific statement from the American Heart Association. Circulation. 2013;128(8):873-934. doi:10.1161/CIR.0b013e31829b5b44 Khurana E, Oommen ER. Determination of cardiovascular fitness in young healthy medical students. IAIM. 2016;3(10):74-78. Vilcant V, Zeltser R. Treadmill stress testing. In: StatPearls [Internet]. StatPearls Publishing. Updated February 13, 2020. Additional Reading Heyward VH, Gibson A. Advanced Fitness Assessment and Exercise Prescription, 7th Edition, The Cooper Institute for Aerobics Research, 2014. Kenney WL, Wilmore JH, Costill DL. Physiology of Sport and Exercise. Human Kinetics, 2012.