Why Would Athletes Consider Testing?
Let’s begin with exploring why athletes typically do physiological testing, how smart and intentional training can often provide the same insights, and which tests are actually useful (and which aren’t) for most endurance athletes. Our goal is to help give you clarity and confidence in focusing on what truly matters in your training.
- There are two main reasons endurance athletes turn to formal physiological tests: To identify limiters to guide training: Formal tests can help pinpoint an athlete’s physiological strengths and weaknesses – for example, checking aerobic capacity vs. top-end speed – so you can tailor training to target the areas that need the most improvement.
- To monitor progress over time: Testing can track how different aspects of fitness are developing. Are your training blocks (endurance, threshold, VO₂ max, etc.) delivering the expected results, or do you need to adjust your approach to training?
1. Determining Your Limiters (Strengths and Weaknesses)
Every athlete has unique strengths and weaknesses- what coaches call limiters, that can hold back performance. Perhaps you have a big aerobic engine but lack top-end speed, or vice versa. Coaches often call these weak spots “limiters” because they limit your performance until they are improved. “Train your weaknesses, race your strengths.” This is a time-honored concept in endurance sport for good reason- if you can identify your physiological limiters, you can tailor your training to improve them and formal testing is one way to find those limiters. g Testing can help identify important physiological thresholds that help a coach or athlete assess their current fitness, detect any imbalances, and target training for best results. . You might learn that your VO₂ max or speed at lactate threshold is relatively low. There might be a large gap between your aerobic and anaerobic thresholds, indicating you could benefit from more work on your aerobic capacity. Perhaps your overall aerobic engine is good, but your lactate threshold – which sits between low-intensity base and high-intensity capacity – is underdeveloped relative to your potential.
In short, testing can shine a light on whether an athlete is limited by high-end power, by aerobic endurance, orby lactate clearing rate and capacity and gives some important guidance on what to focus on in training. For example, an athlete lacking “top end” would be wise to incorporate more high-intensity interval work; one lacking endurance might do more long aerobic sessions; one with a gap at threshold might add tempo/threshold runs. This is the rationale behind testing for limiters – it gives you data to target the right training adaptations.
2. Monitoring Progress and Adjusting the Plan
Another good reason to test is to track improvement. Training is usually organized into phases or blocks (for example, an aerobic base phase, a muscular endurance phase, sport-specific phase, etc.). Athletes often use periodic testing to assess whether the current approach training is working. A well-designed training program has checkpoints built in. After a VO₂ max or endurance focused phase, targeted tests (like hard effort or pace at heart rate) reveal whether key physiological capacities have improved. . This feedback helps coaches decide whether to progress an athlete to the next training phase, set new goals, or adjust the workload if progress is slower than expected. . Testing provides an objective check on training effectiveness: Did this training block increase threshold pace? Is aerobic capacity better than it was two months ago?
While testing provides objective data on training effectiveness, it does require a short taper to ensure reliable results—typically about a week. Balancing testing with training demands is part of effective coaching so that it does not disrupt or detract from the overall training and performance goals.
Formal testing can do two helpful things: identify areas for improvement and confirm training effectiveness. While these are important, lab tests aren’t the only option. Most endurance athletes can diagnose limiters and monitor progress using data from regular training sessions, without ever stepping foot in a lab.
Training as Your Test: Insights from Everyday Workouts
- Do a set of short, hard VO₂max intervals (say 3-minute uphill repeats) – to test your high-end aerobic power. You can see the maximum pace or power you sustain, how your heart rate responds, and how you recover between repeats. That gives insight into your top-end fitness.
- Do a lactate threshold workout – for example, a 30- minute tempo run or uphill climb at a strong and steady effort. This is essentially a lactate threshold test done in the field. You learn what pace or power corresponds to your “red line” sustainable effort, and how your body feels at that intensity.
- Do a longer steady state run on moderate rolling or uphill terrain for an hour). This serves as a test of your strength at sub-threshold intensity.
- Do a long Z1-Z2 aerobic session like a 2-hour easy run or a 4-hour uphill hike. These act as a test of your aerobic endurance capacity. Youcan check if your heart rate stays stable (or “drifts” upward) over the session to gauge your aerobic threshold fitness and fatigue resistance.
Using Training Data to Identify Limiters
Using Training Data to Monitor Progress
Here’s a little trick of the trade: you can track progress by repeating the same workout or route at regular intervals. For instance, if your pace improves on a standard 60-minute run at the same heart rate, that’s a clear sign that your aerobic fitness is improving—no lab test needed. The same applies to hill climb time trials: faster times or lower heart rates show objective gains. Coaches often use these repeatable “checkpoint” workouts, like heart rate drift tests, to set baselines and measure improvement over time. In fact, our Uphill Athlete training plans start with a simple aerobic threshold heart rate drift test to 1) set a baseline so you can determine your correct training heart rate and RPE, and give you a clear way to validate improvements in aerobic base down the road.
The beauty of using your training and data as testing benchmarks is that you’ll get a continuous, real-world view of your fitness, helping you spot trends and make timely adjustments, rather than relying on a single lab snapshot.
From our coaching experience, athletes who learn to listen to their bodies and interpret their training data become more educated and resilient. They’re not just chasing a lab number; they’re understanding how pace, heart rate, power, and perceived effort all interact and impact their performance That understanding is gold for long-term progress.
Lab tests aren’t useless—they can be helpful in certain situations. But you don’t need formal testing to train effectively. Most athletes can get nearly all the benefits through smart training and basic analysis tools like a training log and a GPS watch. A lactate meter isn’t necessary unless you really want to get geeky.
Which Tests Are Useful - and Which Aren’t?
Let’s look at a few common assessments and how we view them through the Uphill Athlete lens:
Lactate Threshold Testing (Lab or Field)
What it is: A test to learn your aerobic (LT1) and anaerobic (LT2) thresholds. These are key points where your body shifts how it produces energy.
The lab version of the test involves running or hiking at progressively increasing intensities while measuring blood lactate levels (via finger or earlobe prick) at each stage. The lab test is often paired with gas exchange analysis to also find both ventilatory thresholds (breathing changes) that correspond to those points.
The field version for determining LT1 would be performing a steady 60-minute effort and taking the average heart rate or pace of the last 20 minutes and comparing excluding the warm up and cool down periods. To approximate AnT/LT2 in a field test, run or hike at a hard steady 30-minute effort. (This is the runner’s classic 30 min time trial test for functional threshold.)
Why It’s Useful: Knowing your aerobic and anaerobic thresholds helps you set your training zones for heart rate, pace,or power. . It also helps identify the balance of your fitness (as we described earlier: base vs. top-end). For experienced athletes, periodic aerobic threshold tests can validate that your base training is moving your LT1 upward, and periodic anaerobic threshold tests validate that your high-intensity work is pushing LT2 higher.
What to Watch Out For: Lab testing requires access to a facility or coach with the equipment, and not everyone has that readily available (plus it can be costly each time). Field tests are free but require a maximal effort which can be taxing and need good execution to be accurate. It’s important to note that thresholds can actually fluctuate day to day based on hydration, glycogen, stress, etc. – so a single test result is not a perfect immutable measurement of you as an athlete. If you’re tired or nervous on test day, the results might underrepresent your ability.
Athletes can estimate their thresholds without a formal test. Uphill Athlete coaches often guide athletes to use a steady-state treadmill or trail effort to look for the heart rate at which breathing noticeably changes or where heart rate starts to drift – this often nails the aerobic threshold. We might also use the talk test: if you can only speak a few words at a time, you’re near LT2; if you can speak in full sentences, you’re below LT1. These low-tech methods align surprisingly well with lab-derived numbers for most people. So, while lactate testing is valuable, it’s not the only way to get the info. We consider it optional but nice-to-have if you’re a data-oriented athlete or have specific reasons to want that precision
VO₂ max Testing
What it is: A lab test that measures the maximum amount of oxygen your body can use during intense exercise– essentially the peak volume of oxygen your body can utilize per minute.
This test is conducted in a lab via an incremental exercise test to exhaustion while wearing a mask that analyzes your oxygen and carbon dioxide breath-by-breath. . The output includes a VO₂ max value (in ml/kg/min) and often additional metrics like ventilatory thresholds and respiratory exchange ratio.
What to Watch Out For: While a VO₂ max lab test is not very actionable for day-to-day training. VO₂ max is an important physiological metric: it indicates the upper limit of your aerobic engine. However, knowing your VO₂ max value doesn’t directly tell you how to structure your training next week. We’ve coached thousands of mountain athletes without ever knowing their exact VO₂ max, and it hasn’t impeded their progress. If your goal is to boast about a number or to qualify for a research study, sure, get it measured. But if your goal is training optimization, VO₂ max itself is usually not the limiter for non-elite athletes – rather, it’s how much of that VO₂ max you can sustain (thresholds, economy, durability), not the maximum utilization itself. Performance gains usually come from improving economy and a higher lactate threshold, not a higher VO₂ max.
VO₂ max changes very slowly– it’s about 80% genetic and plateaus early in an endurance career with continuing gains coming due to sport-economy (efficient movement) and increased fatigue resistance. We generally consider VO₂ max tests “nice to have, but not need to have” It can be fun to learn your number and see how you stack up, and for very advanced athletes it might inform some ultra-specific training tweaks (perhaps if you’re near your genetic ceiling, you’d focus on other areas). But for the majority, time and money are better spent training smartly. If you do a VO₂ max test, do it out of curiosity or for the experience – not because you must have it to train well.
Other Tests and Assessments
What They Are: Tests like critical power, running economy, sweat sodium analysis, gait assessment, and metabolic efficiency can give you some health or performance insight.
When They Are Useful: If you feel that the information you’d get from these test will provide you with information that you can use to better target your training or nutrition, they might be worthwhile. If not, you might think twice.
What to Watch Out For:
Certain tests will provide you with interesting data, but that might not always translate to actionable change.
A good example is a metabolic efficiency test (to determine how much fat vs. carbohydrate you burn at different intensities). It can provide iInteresting data, but you might already be able to learn this from paying attention to your fueling strategy and and noticing how your body responds. Unless you plan to overhaul your nutrition strategy based on test results, it could just be nice trivia. On the other hand, something like an echocardiogram for heart health might be very worthwhile for older athletes or those with risk factors – not to guide training, but to ensure there are no medical issues that might impact training. Some tests are done for health, not performance, and those can be important. Always be clear on the purpose of any test.
The Bottom Line: Train Smart First
So, do we need to test to train well? For athletes working with a coach, most of the time, the answer is no – you can train extremely well without any formal physiological testing. For athletes self-coaching and/or working off a training plan, the answer is you may be wise to test. Once the baseline is set, structuring your training intelligently and paying attention to the results, you will naturally get the feedback you need. Your workouts will tell you where you’re strong and where you’re weak. Your improvements (or struggles) over weeks and months will tell you if your training is effective or needs adjustment.
While formal tests can be a complement to the process, your actual training will give you great feedback. Progress, plateaus, and how you feel during your workouts will all tell you whether your plan is working. Consider testing only if you have a clear plan for how to use the data. Ask yourself: Will this result change how I train or recover? If yes, it could be worth it. If not, your time might be best spent staying focused on your training.
Our Final Take
At Uphill Athlete, we follow a “train smart, test when useful” philosophy. Strong aerobic development, clear threshold zones, muscular endurance, and consistent training matter far more than any single test result. This athlete-centered approach keeps you focused on your big- picture development rather than chasing numbers in a lab.
In the end, the only “test” that truly matters is your performance in your goal activity, be it a race, a climb, or any personal challenge. Training is the process of improving that performance. Everything else – including testing – is just a tool to support training. Use tools wisely if needed, but remember that doing the work, week in and week out, and listening to your body, is the proven path to success.
Train hard, train smart, and let your training teach you what you need to know. Happy training, and see you in the mountains!