According to the American College of Sports Medicine, health related physical fitness includes cardiorespiratory endurance, body composition, muscular strength, endurance and flexibility. Being able to perform well in each of these categories is associated with lower risk of developing disease or functional disability. The purpose of treadmill stress testing is to determine cardiorespiratory fitness. Test findings can also help health professionals assess an individual's cardiovascular health.
Maximal and Submaximal Stress Testing
Whether or not a maximal or submaximal treadmill test is used depends on the reason for the test, the person being tested, and the availability of equipment. The drawback of maximal stress testing is that the individual must exercise until they reach their age predicted maximum heart rate or fatigue, whichever comes first. This type of testing usually requires the presence of a physician. Because maximal testing is not practical for the majority of individuals and fitness practitioners, submaximal testing is more commonly used. The goal of a sumaximal test is to determine heart rate response to submaximal work rates and then predict maximal oxygen uptake.
Testing Procedures
Prior to the test, resting measurements of blood pressure, heart rate, EKG and rate of perceived exertion are recorded. The individual is provided with details of how the test will progress and what measurements will be taken during testing. The rate of perceived exertion scale is explained as well as any safety information.
The individual then gets onto the treadmill and the test begins. The treadmill tests are broken up into stages. The stages occur for a predetermined amount of time and the treadmill protocol is programmed into testing equipment prior to assessment. Heart rate, blood pressure, EKG and rate of perceived exertion are monitored and recorded during testing. The individual is taken through each stage of the test until the desired heart rate is reached, they ask to stop, or test termination is necessary. Information gathered from the test is entered into a formula and maximal oxygen uptake is provided. This information is also used to determine cardiorespiratory fitness.
Bruce Treadmill Protocol
The Bruce treadmill protocol is fairly popular treadmill test. The stages are three minutes in length. There are a total of eight stages if the full test is completed. The treadmill speeds vary from 5.5 miles per hour to 1.7 miles per hour during the test. The treadmill incline varies from 20 percent to 5 percent incline.
Balke-Ware
The Balke-Ware treadmill protocol is another popular treadmill stress test. There are a total of 26 stages if the test goes to completion. During the Balke-Ware protocol, the treadmill speed remains constant at 3.3 miles per hour. The stages for this test are one minute in length and the treadmill incline starts at 26 percent and decrease to 1 percent.
Ellestad
The Ellestad treadmill protocol alternates between three, two, and three-minute stages. There are a total of 6 stages if the test goes to completion. Treadmill speeds vary from 6 to 1.7 miles per hour and grades vary from 15 to 10 percent incline.
References
- "ACSM's Guidelines for Exercise Testing and Prescription 6th edition": American College of Sports Medicine: 2009.
- American Heart Association: Exercise Stress Test
