Entering winter, as well as transitioning out of the cold-weather months and into spring, are the times riders ask us most to explain the differences between testing their Functional Threshold Power (FTP) outdoors versus indoors. The truth is, there are a lot of variances between the two approaches. However, the goal of assessing FTP is to provide an accurate picture of your fitness so that your future workouts are calibrated to the correct intensity. For now, let\u2019s dive into why you should test your FTP and how to test it indoors and outside. <\/p>\n\n\n\n
If you\u2019re a TrainerRoad<\/a> athlete, it\u2019s likely you already know the weighty reason we advocate for knowing your FTP. Once we know your FTP, we\u2019re able to customize every workout you do so that it\u2019s optimized to your current fitness level. The more precise your FTP is, or perhaps better said, the more precise your FTP estimate is, the more effective your future workouts will be. That\u2019s why, instead of going in with a previously estimated FTP, the first workout we highly encourage all our athletes to complete is the Ramp Test<\/a>.<\/p>\n\n\n\n Adaptive Training<\/p>\n Get the right workout, every time<\/strong>\n with training that adapts to you.<\/p>\n Check Out TrainerRoad<\/a>\n <\/div>\n<\/div>\n\n\n\n If you\u2019re not a TrainerRoad athlete, the same reasons to know your FTP apply. Firstly, once you\u2019ve correctly estimated your FTP, you will have a benchmark of your fitness, which will help inform you in the future on whether you\u2019re getting faster or not. Secondly, after you know your FTP, you\u2019re able to use that information to structure your interval workouts more effectively. So, instead of going into a workout saying, \u201cI\u2019m going to ride at an 8 out of 10 or 6 out of 10,\u201d you have an objective number. This allows you to figure out exactly what your power numbers need to be\u2014no guesswork involved.<\/p>\n\n\n\n Assessing your FTP indoors is the best choice for several reasons. The most important reason is that you can control the variables much more closely than with an outside test. Aside from being more convenient, you have the advantage of limiting the number of variables like traffic, wind, road quality, and variations in pitch you would otherwise experience outside. For a scientific test like the FTP test, this is key.<\/p>\n\n\n\n TrainerRoad\u2019s preferred FTP assessment is our Ramp Test<\/a>. The Ramp Test begins with a 5-minute warmup, and then every minute thereafter, it gets slightly harder until you cannot maintain target power any longer. 75% of the best one-minute power you achieve during the test is used as your FTP. The TrainerRoad app will automatically calculate this for you. <\/p>\n\n\n\n Our data shows the Ramp Test results in the most accurate and useful FTP estimate for the majority of riders using TrainerRoad. Since it is quick (typically about 25 minutes, including warmup and cooldown) and fairly easy, it can be taken frequently to track your fitness changes. <\/p>\n\n\n\n When performing your 20 or 8-minute FTP test indoors, start with 20 minutes of warming up, followed by your testing efforts, concluding with a 10-minute cooldown. After your test, calculate the average power of your testing interval(s) and reduce the number by 5 or 10 percent. Again, reduce by 10 percent if you did an 8-minute effort and by 5 percent if you did a 20-minute effort.<\/p>\n\n\n\n To decide if the 8-minute or 20-minute FTP test is right for you, consider your primary cycling discipline and your experience. For shorter duration athletes who are used to performing at VO2max<\/a>, we commonly recommend an 8-minute FTP test. These are criterium racers, cyclocross racers, and cross country mountain bikers \u2014 riders who are generally more accustomed to working at this uncomfortably high workload.<\/p>\n\n\n\n For athletes who are used to putting out longer, sustained efforts in their races, we almost always recommend a 20-minute FTP test. These are road racers, triathletes, 40-kilometer time trialists, endurance mountain bikers, and gravel racers \u2014 riders who are used to laying down longer, very evenly paced efforts.<\/p>\n\n\n\n All this information aside, we designed the Ramp Test to make testing simpler without the hassle of deciding which test and removing the need for pacing<\/strong>. Whichever way you choose to test, stick with it. Consistency is vital when it comes to tracking progress. <\/p>\n\n\n\n If you use TrainerRoad, you can expect a more strategically structured warm-up when you perform one of our FTP tests. Each FTP test includes a warm-up that consists of a few big efforts\u2014these peaks of intensity are specifically designed to prepare you for the testing intervals ahead.<\/p>\n\n\n\n The warm-up for the 8-minute test includes higher, shorter, and more intense intervals than the 20-minute test. In either case, the intense warm-up efforts we prescribe are driven by one goal: to thoroughly prepare your body and mind for the upcoming intensity. After you\u2019ve completed your FTP test on TrainerRoad, we will present you with your new FTP. Once you accept it, all your workouts will be automatically customized to your new FTP.<\/p>\n\n\n\n Many riders think that to perform their FTP test outside, they need to find a hill to reduce variables and be more consistent. The issue with this kind of thinking is that you\u2019re inserting a huge variable just by going uphill instead of on a flat. There\u2019s less inertia when you\u2019re going uphill, which means all the way around your pedal stroke, you\u2019re forced to apply more pressure on the pedals.<\/p>\n\n\n\n This can make a measurable difference in the way your muscles put down power than if you\u2019re riding fast on flat ground. So right there is a big variable you\u2019re inserting by assuming that your FTP estimate is the same uphill as it is on any other type of terrain.<\/p>\n\n\n\n Your best approach is to find a stretch of uniform road that you can put out power consistently without interruption for either 8 or 20 minutes. Depending on the type of athlete you are and your testing experience, finding either an 8- or 20-minute stretch of road will be more or less important to you. Put in another way: It\u2019s best not to decide on the stretch of road you find for testing purely based on convenience, although that\u2019s understandably a factor. Let me explain:<\/p>\n\n\n\n Once you\u2019ve decided on the testing format that\u2019s right for you and scouted out your stretch of flat road, here\u2019s how to execute the day of the test:<\/strong><\/p>\n\n\n\n Although it\u2019s more difficult to reduce variables when performing your FTP test outdoors compared to indoors, there are still factors you should keep in mind and control as much as possible. <\/p>\n\n\n\n By taking the time to do a little post-race analysis you can quickly get a feel for what your FTP is. The approach is simple: Look at a race where you\u2019ve had to put out a consistent, all-out effort for 8 minutes, 20 minutes or even an hour. (It\u2019s important to note this can be tricky as races are often anything but consistent, especially when you\u2019re riding with others.) Next, calculate your average power \u2014 not normalized power<\/a> \u2014 for your 8- or 20-minute effort. Finally, reduce your average power by 10 percent if you\u2019re using an 8-minute effort or by 5 percent if you\u2019re using a 20-minute effort.<\/p>\n\n\n\n Why do you have to adjust your average power?<\/strong> FTP is analogous to your hour power \u2014 or at least it\u2019s supposed to be. For most, it\u2019s not. This has a lot to do with the mental fortitude it takes to ride at your highest possible limit consistently for an hour-long duration. This is tough!<\/p>\n\n\n\n Most athletes mentally limit themselves before their body physically does. This is the impetus of an FTP test \u2014 it\u2019s the reason you can do shorter intervals to decipher your hour power. When you test for shorter durations, mental strength isn\u2019t as big of a variable which means you can get a better idea of your physical potential rather than having mental limiters come into play and mess with your power results.<\/p>\n\n\n\n The longer you ride, the smaller the percentage you have to reduce your average power. Why? More likely than not, your max 20-minute effort is going to be higher than your max 60-minute effort. Same thing goes with your max 8-minute effort\u2014it\u2019ll likely be even<\/em> higher than your 20- and 60-minute maximum efforts. That said, reductions of 5 or 10 percent are established protocols that are proven to roughly equate most closely to your true FTP, aka your 60-minute power.<\/p>\n\n\n\n What about if you have an hour-long race file you want to analyze to find your FTP? As long as it is a well-paced and consistent effort, this is actually an excellent way to measure FTP. With this approach, you do not have to reduce the percentage of your power\u2014the estimate is what it is.<\/p>\n\n\n\n A lot of athletes will report they have a lower FTP when they test indoors than when they test outdoors, and sometimes vice versa. There could be a number of reasons for this, but a good one to look to first is thermoregulation. About 75% of your body\u2019s energy consumption when cycling goes to cooling, or maintaining your body\u2019s temperature. When you\u2019re outdoors this is better-achieved thanks to wind and sometimes temperature. But indoors, you\u2019re reliant on a fan or another cooling mechanism to keep your body from having to work so hard to stay cool.<\/p>\n\n\n\n We could go on and on in this section and try to dissect every little variable that could lead to a difference in test results, but ultimately I think it\u2019s better to end this post simply: Because there are less variables to consider, assessing your FTP inside will provide more sound data, i.e. accurate assessment results, than what you\u2019ll get outside. What\u2019s more, because there are so many variables and differences to consider between the two approaches, you simply cannot compare your test data from an outdoor test to your test data from an indoor test, and vice versa. <\/p>\n\n\n\nHow to Calculate Your FTP Indoors<\/h2>\n\n\n\n
Ramp Test<\/h4>\n\n\n\n
20-minute and 8-minute Tests<\/h4>\n\n\n\n
Should I Complete the 20-minute or 8-minute Test?<\/h4>\n\n\n\n
Completing a 20-minute or 8-minute Test<\/h4>\n\n\n\n
Indoor Testing Variables<\/h2>\n\n\n\n
How to Calculate Your FTP By Testing Outdoors<\/strong><\/h2>\n\n\n\n
Outdoor Testing Variables<\/h2>\n\n\n\n
How to Calculate Your FTP By Looking at a Power File<\/strong><\/h2>\n\n\n\n
The Differences Between Testing Outdoors vs. Indoors<\/strong><\/h2>\n\n\n\n