The Bruce Protocol Treadmill Test for Athletes

A Fitness Evaluation Used to Measure VO2 Max

VO2 Max Treadmill Testing
VO2 Max Treadmill Testing. Dan Kitwood / Staff / Getty Images

Testing an athlete's fitness levels can take a variety of forms. There are specific tests for strength, endurance, agility, speed, and power. There are also a variety of clinical tests to evaluation lactic threshold (LT), muscle endurance, lung capacity and even heart functions. 

One noninvasive test for estimating the overall fitness of endurance athletes was originally designed in 1963 by Robert.

A. Bruce, MD, 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. Known today as the Bruce treadmill test, it is still being used to assess endurance athlete's overall fitness levels.

What Is V02 Max - Maximal Oxygen Uptake

Today, the Bruce Protocol is a common method for estimating VO2 max in athletes. VO2 max, or maximal oxygen uptake, is one factor that can determine an athlete's capacity to perform sustained exercise and is linked to aerobic endurance.

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 that estimates VO2 max using a formula and an athlete's ability to exercise on a treadmill as the workload is increased.

Other methods of measuring VO2 Max are much 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. This collection determines how much oxygen the athlete is using as they run. Clearly, that sort of direct testing would require far more elaborate and sophisticated equipment and data collection that the formula based upon time on the treadmill.

How to Estimate VO2 Max Using the Bruce Treadmill Test

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 (See chart). 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.

VO2 Treadmill Testing Cautions 

Because the Bruce treadmill test is a maximal exercise tolerance test, it is not something to be done without 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 potential heart events. While performing the treadmill stress test, clinicians will monitor the patient's vital signs continuously and stop the test at any sign of trouble.

For an athlete, an experienced technician should monitor heart rate and rhythm throughout the testing. Be sure that your testing facilitator has the appropriate clinical expertise and has conducted such tests many times before you step on the treadmill for your own testing.

Bruce Treadmill Test Stages

Stage 1 = 1.7 mph at 10% Grade
Stage 2 = 2.5 mph at 12% Grade
Stage 3 = 3.4 mph at 14% Grade
Stage 4 = 4.2 mph at 16% Grade
Stage 5 = 5.0 mph at 18% Grade
Stage 6 = 5.5 mph at 20% Grade
Stage 7 = 6.0 mph at 22% Grade
Stage 8 = 6.5 mph at 24% Grade
Stage 9 = 7.0 mph at 26% Grade

The Bruce Protocol Formula for Estimating VO2 Max

  • 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
  • T = Total time on the treadmill measured as a fraction of a minute (ie: A test time of 9 minutes 30 seconds would be written as T=9.5).

Because this is a maximal exercise test, it should not be performed without a physician's approval and without reasonable safety accommodations and supervision.

Bruce Protocol Norms for Men

VO2 Max Norms for Men - Measured in ml/kg/min
AgeVery PoorPoorFairGoodExcellentSuperior
13-19 35.0-38.338.4-45.145.2-50.951.0-55.9>55.9
20-29 33.0-36.436.5-42.442.5-46.446.5-52.4>52.4
30-39 31.5-35.435.5-40.941.0-44.945.0-49.4>49.4
40-49 30.2-33.533.6-38.939.0-43.743.8-48.0>48.0
50-59 26.1-30.931.0-35.735.8-40.941.0-45.3>45.3
60+ 20.5-26.026.1-32.232.3-36.436.5-44.2>44.2


Sources: 

Wilmore JH and Costill DL. (2005) Physiology of Sport and Exercise: 3rd Edition. Champaign, IL: Human Kinetics.

Vivian H. Heyward, Advance Fitness Assessment & Exercise Prescription, 3rd Edition, The Cooper Institute for Aerobics Research, Dallas TX, 1998.

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