Testing Your Fitness
As someone who’s studied Exercise Physiology but also put those studies to practice through coaching and training for my own Ultras, I find Fitness Testing to be one of the more fascinating aspects of the ultra experience. How do you really know if the training that you are doing is helping you to improve as an athlete? The answer is data. The best way to get this data is though careful testing. During my undergraduate studies I was always in the performance lab doing tests on myself and others. I was so fascinated by what those tests tell us about how our bodies respond to training stimulus that opened my own performance lab to test runners. In this post I will discuss my thoughts on the more important tests to perform for ultrarunners and what to look for as your training progresses. We’ll start out with the tests that are included with the Ultra App and then round out the discussion with some additional tests that I think may be beneficial.
HRmax and VT Test
This is one of the 2 treadmill tests that are available on Ultra App. This test was designed through lots of trial and error in a sports performance lab to best determine the athletes actual maximum HR and VT.
The first test is a HRmax and Ventilatory Threshold (VT) Test. This test has 2 purposes, determine your actual HRmax and determine your VT (pretty obvious from the description of the test). The benefit to this test is really to set your training HR zones (Zone 1, 4, and 5). Since ultrarunners rarely venture into these zones when training and racing this test is less important than the other treadmill test but still important for setting your HR zones. This test is performed on a treadmill and follows the same protocol each time you perform the test. This is my own protocol but is very similar to many other VO2max protocols that you may see performed at a performance lab. The purpose of this test is to try and get the runner to a maximal level of cardiopulmonary output without causing too much fatigue to the active muscles. This is done by using a “ramp” method. The ramp method uses 1 minute stages that increase in speed and incline. The idea is to get the runner to a maximal effort in less than 12 minutes of testing. This test starts out at 1% incline and 5 mph on the treadmill and increases by 0.5% and 0.5 mph every minute. The last stage would be 6.5% incline at 10.5 mph. This will be suitable for almost every runner to achieve a maximal effort. If you are an Elite or Professional athlete you may need to start the test at a faster pace to ensure you hit a true max by the last stage. The highest HR that you achieve during this test (presumably right at the end) will be your true HRmax. I find it extremely helpful to know your true HRmax because the formulas that are used are almost never right (and most times not even close).
VT is obtained by the user pressing the “VT” button on the app when they experience a drastic increase in ventilation. In Exercise Physiology, the VT is also very close to the lactate threshold. We consider this to be your “Threshold Pace” or Zone 4. For ultrarunners this is not a terribly critical data point and not something that needs to be a focus of training. If you are a collegiate 1500m or 5K runner, your main focus will be trying to drive up your VT or threshold pace. In ultrarunning you might have a few sessions that will call for a zone 4 effort but it is certainly not a focus of training. It is, however, another data point that can be tracked and is also useful for clearly determining the cutoffs between the HR zones.
Aerobic Endurance Testing
This is the second treadmill test available on Ultra App which very closely pinpoints the runner’s Aerobic Threshold and sets the Zone 2 HR for training. This test also tracks Running Economy.
The second test that is performed in Ultra App is the most important. The HRmax test sets up the foundation for your HR training zones but the Aerobic Endurance Test is where you will measure your fitness gains. This test is also performed on a treadmill using a “step” protocol. The difference between this test and the HRmax test is that during this test we want your HR to normalize during each stage. For this reason, we do not increase the incline (only speed) and each stage is 3 minutes in length. You start out at a slow pace and increase the speed by 0.5 mph every stage. You will very likely not reach your HRmax during this test. Ideally, you will get up to your VT heart rate that you saw during the first treadmill test but that is also not mandatory. It is not easy to determine your actual Aerobic Threshold (AeT) without using an Indirect Calorimetry device (O2 and CO2 sensors hooked up to a computer which analyzes your breath while wearing a mask during the test). To do this, I use a method that very closely mimics the effort level that you experience when you hit your AeT. This is called the nose test. You will start the treadmill test by only breathing through your nose. Once you reach a pace that you can no longer EASILY breathe through your nose only (and have to start breathing through your mouth as well) you hit the “NT” button on the app and it records your HR and pace at your AeT. This is not a perfect test, but is much more accurate than any other formulas or calculations out there. The AeT is going to be your most critical HR zone (Zone 2) since you will spend the vast majority of your time training in this zone. As your aerobic fitness improves you will likely find that your HR at AeT and especially your pace at AeT will improve.
The other data point that is collected during this test is Running Economy (RE). In my opinion, RE is the best single data point to track for fitness improvement. VO2max used to be the gold standard but there are many issues with VO2max testing and besides it is fairly unimportant for ultrarunners (except for very high level elites) as a measure of how well you will finish a race. Running Economy is basically a measure of how efficient your body is at a given pace. For the Ultra App, I chose 8:00/mi pace as the benchmark for testing RE. The app will record your HR at this pace when you hit it during the test. If your fitness is improving, your HR will be lower at this pace as you progress through your training plan. The reason I like RE better than VO2max is that it gives a much better overall picture of your fitness (especially at sub max pace). It is very common to have a runner with a VO2max of 70 run much faster than another runner with a VO2max of 80. Does the runner with VO2max of 80 still have more fitness than the runner with 70? I argue not. RE takes into account muscle efficiency gained through strengthening as well as cardiorespiratory improvements. Economy of motion is how the 70 VO2max runner can be faster than the 80 VO2max runner. If your HR at 8:00/mi goes from 165 down to 155 in a month of training then you are getting more fit!
Sweat Test
This test is less about your fitness and more about understanding how much you need to hydrate during the race. It is still a very critical test to perform prior to race day so that you can plan your hydration strategy. The best way to complete this test is in a controlled environment that is as close to race conditions as you can get. This means that you should find out typical temperatures and humidity levels in the race location for that time of year and try your best to mimic it. I always prefer to do testing on a treadmill and in a controlled environment so that you can limit the number of variables that impact the outcome of the test. Once you have the environment set up, you will need to get a pre-run weight. You should weigh yourself without any clothes on. The goal for this session is to run at your goal race pace for an hour without eating or drinking anything (or going to the bathroom). Once you have completed the 1 hour run, (before eating or drinking) strip off your sweaty clothes and dry yourself off with a towel. Step on the scale again and record the difference in weight. It is not uncommon to lose several pounds over this hour. 1 pound of water (sweat) = 16 oz. If you have lost 2 pounds during that 1 hour run, then you have sweat out ~32 oz of sweat. The goal is to replace nearly as much fluid per hour as you lose. This might not be possible for some of the heavy sweaters out there but you should try to replace 80-90% of the fluid that you lose. Once you have this number figured out you should start “training” your gut to be able to handle the higher volume of fluids that you’ll be taking in.
VO2max Testing
I have performed dozens of VO2max tests and administered dozens to other runners. My personal opinion is that they are useful for shorter distances (possibly up to marathon) but are less important for the ultrarunner. VO2max is not something that just anyone can do. You will not get an accurate (or even close) number by going off of Garmin or any other device that “calculates” VO2max. There is a very specialized machine which measures the amount of oxygen and CO2 in your breath as you exercise. This machine is called a metabolic cart and is typically only found in labs that do exercise testing. You can find a lab that does this test if you are really interested in the data and numbers but I can assure you that tracking this data is less important than you may think. For runners who are already in shape, you may not see any increase in VO2max while your fitness is still obviously increasing (this is why I prefer to use Running Economy).
Metabolic Testing
This test is far more interesting to me but again must be done using the metabolic cart that is used for VO2max testing. An experienced exercise scientist can evaluate the results of the VO2max test and determine what percentage of fat vs. carbs you are burning in your separate training zones. I honestly prefer to do the Aerobic Endurance treadmill test (outlined above) for this because you will get better readings using the step protocol rather than the typical ramp protocol used in VO2max testing. Again, this should be done by an experienced exercise scientist who understands what they are looking for. I have tested many fat-adapted athletes who burn 95% fat as fuel during Zone 2 paces and even 90% in Zone 3. Using these calculations, you can accurately determine how many calories of carbohydrate you need per hour of fueling during race day. This can be a very helpful test but it’s not easy to find someone who knows how to do it.
There are a multitude of other tests that coaches like to have their athletes perform. There are others that may be important for your specific situation. What I’ve outlined here are the most important/popular tests that I’ve performed as a coach, runner, and performance lab owner. In my opinion, testing should always be prioritized over using formulas to determine your actual fitness. I have seen it many times where the formulas have predicted numbers that were way off resulting in either injury or sub-par performance.