VO2 max tests are used to determine the maximum amount of oxygen an athlete's body can use during intense, sustained physical activity. Athletes strive to increase their VO2 max performance to improve endurance and stamina, and in order to determine how much improvement the athlete needs, VO2 max tests are used. While VO2 max tests can vary from sport to sport, the general concept is the same: measure the heart rate of the individual, ramp up the heart rate to the most optimal training rate, sustain the exercise for an established period of time, and measure how much oxygen is being used.
The most common version of VO2 max tests involves an athlete either running on a treadmill or cycling on a bicycle. The athlete is hooked up to a mask that measures oxygen intake by collecting expired carbon dioxide in a bag or container during the duration of the test. The athlete must be in fairly good shape in order to do the test, as it is rigorous and has the athlete performing above his or her normal peak. While the athlete is running or cycling, a trainer will be standing by to time the test as well as to increase the intensity of the workout from moderate to maximal. At the end of the test, a special tool is used to measure how much oxygen was used during the peak of the exercise.
Since this version of the VO2 max tests can be cost-prohibitive due to the equipment and manpower involved, a simpler test exists that can only help estimate VO2 max. The Balke test was developed by Bruno Balke with the intent of helping runners determine their own VO2 max. The test is usually done outdoors on a windless day, but it can also be done indoors on a treadmill. The runner will run at a constant speed, as hard and fast as possible, for fifteen minutes. A trainer is usually standing by to ensure the runner is maintaining a hard and fast pace. The trainer will also note the distance the runner has covered during that fifteen minutes.
Once the test is completed, a mathematical equation is used to determine the runner's VO2 max. The idea is that the runner's VO2 max will increase over successive testing periods, as the runner trains to increase VO2 max. Progress is determined by measuring the distance covered during the fifteen minute workout. Generally speaking, if the runner covers more distance during the run, VO2 max is improving. The trainer uses the mathematical equation to support this hypothesis, though this test can only give an estimate as to how much the runner is really improving.