Bruce Protocol

Introduction

Maximal oxygen uptake is defined as the region in which oxygen consumption plateaus or increases only slightly with additional increases in exercise intensity. Maximal oxygen uptake is also known as maximal oxygen consumption, maximal aerobic power, aerobic capacity, or VO2 max. The maximal oxygen uptake (VO2 max) is a measure of a subject's ability to take in and utilize oxygen during exercise. A subject with a greater VO2 max value will exhibit greater potential to sustain high intensity exercise for an extended length of time. Theoretically, subjects with greater VO2 max values possess greater concentrations of hemoglobin in the blood, thus enabling them to utilize more oxygen during intense exercise.

The first VO2 Max test performed was the YMCA Bike Test. This test was performed on a cycle ergometer which was calibrated by the test administer. The bike test predicts maximal oxygen consumption (VO2 max) based upon the steady-state heart rate during exercise. Heart rate is measured in how many beats per 15 seconds and multiplied by 4 and then recorded. The initial resistance load is .5 kp and may increase based on heart rate measurements at the end of the third minute. Subsequently, the resistance load is then increased every three minutes (i.e., load settings based on a chart) until the end of the test. VO2 max may be determined from the estimated workload at maximal heart rate. This is determined graphically from two points on a scale of heart rate vs. workload produced which is plotted on a graph.

The second test performed was the Bruce Treadmill Test. This test protocol is used to obtain VO2 max measurements and is ultimately the most popular among the testing of athletes. The main strength of this test is that it is a direct measure of maximal oxygen consumption. This test indicates a subject's aptitude for success in prolonged events as well as the level of health of subjects' cardiovascular and respiratory systems. The test consisted of five 3-minute stages, in which you are able to walk the first three stages. During each stage, a set percent treadmill grade and speed is obtained. During the test, the subjects' breathing and heart rates are monitored through the use of respiratory and metabolic/gas equipment along with heart rate monitors. At each stage all of the data is recorded according to the protocol. The test is over when the participant is no longer able to continue or when all of the criteria have been met.

One of the most effective methods of determining the predominant energy system used during the VO2 max tests performed is by monitoring the heart rate of the participant. Heart rate monitoring helps to determine the intensity of the test performed as well as estimate the heart rate at which the participant made the transition from anerobic to aerobic exercise (i.e., from carbohydrate and fat usage to predominantly carbohydrate). While the transition point differs from person to person, you can get a general idea of where the transition occurs from anerobic to aerobic exercise by watching for substantial increases in heart rate, muscle fatigue, or in breathing depth and frequency. If you are truly engaging in anaerobic exercise, you will not be able to sustain the intensity of the exercise for longer than about one to two minutes. In contrast, when the Bruce Treadmill test was performed by the participant, the aerobic energy system was utilized for this specific test.

The two tests performed during the lab were very useful in obtaining data for VO2 max measurements. The YMCA Bike Test did not solidify a true measure of VO2 max for the participant. The subject did not reach full VO2 max requirements and therefore this test was not valid for a true measure of VO2 max. The Bruce Treadmill Test was the only test that provided a valid measure of the participants VO2 max. This test provided all of the criteria needed to calculate VO2 max as opposed to the YMCA Bike Test which the participant did not reach their full capacity to utilize oxygen.

There are many benefits of performing a VO2 max test on athletes. The main benefit is that it is a direct measure of oxygen uptake. Any athlete would benefit from this test because not only does it measure VO2 max, but it also provides information about respitory exchange ratio, maximal heart rate, and plateau of VO2 with an increase in work rate. The VO2 max test is not limited to certain athletes or individuals. With this testing, one can determine fitness and develop conditioning programs to improve performance unique to each individual. The test establishes an athletes metabolic profile, including a measurement of peak oxygen uptake.

Discussion

When the participant