Measuring Aerobic Capacity

Understanding how to conduct baseline assessment – specifically cardiovascular assessment – is an important part of preparing to become a fitness professional.  Chapter 6 of the ACE Personal Trainer Manual 3rd edition focuses on Testing and Evaluation, and is a great place to start.

There are two primary ways we determine an individual’s aerobic capacity. We can measure it directly, or we can estimate it. Direct measurement of aerobic capacity, or maximal oxygen uptake, is the most accurate method but requires specialized equipment that is typically found only in labs or clinical research facilities. This type of testing is usually performed in the presence of a physician trained in advanced cardiac life support.

Estimating aerobic capacity, on the other hand, can be done with submaximal workloads or tests. The equipment needed for these types of tests is more accessible to personal trainers and other fitness professionals. While there may be some error in the estimation of maximal oxygen uptake, comparison between the initial test and future tests can provide an idea of relative change in aerobic fitness. To keep a cardiovascular fitness test submaximal, the intensity should not exceed 85% of heart rate reserve.

Submaximal tests come in two primary formats – graded exercise test or field test. A graded exercise test (GXT) is a test in which the intensity or workload is increased at predetermined stages, based on specific criteria.

Examples of a GXT include the YMCA Submaximal Bike Test (pg. 177) and the Ross Submaximal Treadmill Protocol (pg. 178).  Field tests can include the McArdle Step Test (pg.180), the Rockport Fitness Walking Test (pg. 180), and the BYU Jog Test (pg. 182).

Which test you conduct with a client will depend on the equipment you have and the client you are working with. Is there a specific need to do a GXT with your client? These tests can be considered ‘strenuous’ by first time exercisers. However, they do provide the best estimate of maximal oxygen uptake. If you have space issues, or you are transporting equipment to your client’s location, then a field test may be more appropriate.

When considering your client, or the client in your exam question, look again for key words that could indicate one test over the other. The McArdle Step Test is better for ‘fit’ people, while the Rockport Fitness Walking Test might be better suited for those with a low to moderate fitness level. Bike tests can cause localized muscle fatigue (quadriceps), but some people have never walked on a treadmill before and might have a significant learning curve. Would it be appropriate to test a 60 year old new exerciser using the BYU Jog Test? The test you choose, or don’t choose, can be an important part of your client’s success.

Questions? Contact one of our Education Consultants at 1-888-825-3636 x782