Metabolic Field Testing

By Michael Ross, MD, Sports Medicine Editor

Metabolic Field Testing

Have you ever shown up at the doctor’s office and, suddenly, your main problem has gone away? I’m sure you have, because it happens all the time. Usually there is some sort of provocative test that can make the symptoms return. The same is true with metabolic testing. Oftentimes, anyone with symptoms usually exhibits the same symptoms during cardiopulmonary exercise testing in the lab, however, some people are more difficult to diagnose. Whether it’s a fear of running fast on a treadmill, environmental issues, or poor performance when not exercising in the real world, sometimes a field test is necessary.


Why field test?

Field testing is frequently used to check your performance on a certain course or climb, such as how quickly you might be able to get up the Manayunk Wall or how fast you can run your favorite loop. However, simply repeating the same course for time will limit how much you learn about your performance. Perhaps there is a headwind slowing you down, but you are actually working harder than your last test. Your time might not be significantly better. Through metabolic  field testing, you can see your improvement on a breath by breath analysis.

What should you learn from a field test?

Ideally, a test in the field should be as accurate and informative as a lab test, only outside the walls of the lab. If you are using field testing to benchmark your performance, you should be able to learn if your training is making you faster. You can also use a field test to guide your training. If your goal is to do well on a certain course, then you should be tested on that course in order to give you all the metabolic information you need to guide your training.

As an example:

The Manayunk Wall hill climb whether you are doing a single repeat or riding it 10 times. If your goal is to climb it in a certain time, then you need to know how hard you are working as you climb it so that you can train at that intensity. With metabolic field testing, we can see what your heart, lungs, and muscles are doing and how to train them most effectively.

Suppose you are approaching your VO2max as you climb the wall, then you need to train at that intensity to increase the time that it would take to get up the wall. Because wattage will go up as you get more fit, relying on watts alone will cause your training to come up short as you get stronger. If you know your metabolic numbers, you can train based upon the watts that you are putting out at that intensity.

Diagnostic v training

One of the main issues that we examine at The Performance Lab is exercise intolerance from medical factors that affect one’s ability to perform at his or her best. Usually, we can detect these factors in the lab setting, but I have worked with several athletes, professionals included, who cannot produce the same level of intensity in the lab as they can in the field. Because they are unable to reach their maximum exertion, they need to be tested in the field, especially if we are trying to reproduce symptoms that only come on during specific training or racing situations. Frequently, these location specific symptoms are due to something that exists in the field, such as pollen, dust, or wind. By bringing the testing into the field, we learn what is affecting their performance.

Cases from the vault:

Kevin has always had a cough after exercise, especially in the cold weather. He thought this was normal and had even given it the nickname “Pursuiter’s Hack.” As cyclocross season approached, he felt the cough was getting worse and was associated with colder weather. He came to the Performance Lab for evaluation. Cardiopulmonary Exercise Testing in the lab showed some mild inflammation of his lungs, but even continued lung measurements during his VO2max testing didn’t bring about his symptoms. We decided to take his testing outdoors. Upon being exposed to the cold air, we immediately saw his altered breathing patterns. His testing after exercise outside revealed what we had suspected all along. Because he didn’t respond to the first-line asthma medications, we had to bring out a stronger medication. He is now riding and competing in road and cyclocross races without difficulty and doing well.

Course-specific performance:

Mark is a road racer who favors criteriums, a short technical course that is raced over many laps. His favorite “crit” is one that involves a short, steep hill. He came to the Rothman Institute Performance Lab to help his performance in this race.  After his baseline exercise testing in the lab, his VO2max, heart rate profile, lung function, and anaerobic threshold were established. We then packed up and headed out to the criterium course. He was fitted with the portable metabolic testing system and rode up the hill several times at race pace. Tracking his VO2 data, we learned that he was riding up the hill consistently at 90% of his VO2max. We now had an interval intensity that he could use to train for the many times he would face this hill in the race. From there, conducting a training program was simple.

Most times, laboratory testing will yield appropriate diagnoses and training numbers, however, sometimes the feel of the road or trail is needed to motivate an athlete to go harder than normally possible in the lab. Thanks to improving technology, reliable, quality exercise testing equipment is portable and allows a base station to receive breath by breath analysis of metabolic function from up to a kilometer away. This new technology opens up the door for diagnosis of disease and to improve training.

Michael Ross, MD Dr. Micheal Ross is a sports medicine physician who has been treating endurance athletes for over a decade. He has been a team physician for numerous professional cycling teams. He also runs the Rothman Institute Performance Lab, a medical and scientific exercise testing and training facility in Bryn Mawr, Pennsylvania. He has written two books on training and sports medicine for endurance athletes as well as multiple scientific papers. He has been an invited speaker at USA cycling and consulted for several bicycle companies to provide the optimum fit. He is an avid triathlete himself who has qualified for short course triathlon nationals several times. When he is not at work or spending time with his family he can be found on the trails and the roads around Philadelphia.