How to use a cycling power meter to train for mountain bike
23/03/23
Cycling power meters have been used on both the road and track for literally decades, but they are not as widely embraced throughout the mountain bike fraternity, which is understandable given the different technical and physiological demands required by MTB racing.
Road and track tend to offer more opportunities for steady state work and you can see what power and corresponding heart rates were produced for the entire ride and also specific sections of the ride. This enables some deep diving on the numbers and also gives a clear idea of exactly how hard you are working.
The demands of MTB can be very different. Rides can be punctuated with brief and sharp climbs requiring sudden and relatively brief increases in power output and heart rate. Not ideal when you are trying to train with total specificity.The key then when training with a power meter on an MTB is to find a circuit that doesn’t require you to constantly be at FTP (more below) or above most of the time so that the effort can be controlled and measured.
In any event, one of your goals will surely be to hit certain power numbers aimed at improving distinct areas of fitness. Let’s take a look at these fitness areas.
1. Determine your FTP: Your Functional Threshold Power (FTP) is the maximum power you can sustain for an hour. You can determine your FTP by taking a 20-minute all-out effort and multiplying the average power by 0.95. This will give you an estimate of your FTP. Always conduct this test either on a stationary trainer or a safe road.
2. Establish your power zones: Once you know your FTP, you can set your power zones. These zones are based on a percentage of your FTP and can help you determine how hard you should be working during a ride. For example, Zone 2 is typically 56-75% of FTP, and Zone 4 is 91-105% of FTP.
3. Plan your workouts: Based on your power zones, you can plan your workouts. For example, if you want to improve your endurance, you can plan a long ride in Zone 2. If you want to improve your anaerobic capacity, you can plan intervals in Zone 4. Decide where you think your performance can be most improved given current capabilities.
4. Monitor your progress: Use your power meter to monitor your progress over time. You can track your power output during a ride and compare it to previous rides. You can also use software to analyse your data and track your progress. But, remember, using a power meter is just one tool to help you train on a mountain bike. It's important to also focus on other aspects of training, such as technique, nutrition, and recovery. In particular technique can be key for smooth and efficient navigation of the terrain.
So, making use of a cycling power meter when training on an MTB isn’t too dissimilar to training for other specific cycling disciplines such as road or track, the basic thinking is the same. Determine your FTP, establish your power zones, plan your workouts based on your power zones after deciding whether you are looking to increase either aerobic or anaerobic capacity and monitor your progress over time. What is different is the effect of the terrain on your ability to train methodically, and so care should be taken when selecting your training rides.
What is also crucial is ensuring that your choice of power meter is consistent AND accurate at all times. There is a school of thought that says that uniform inconsistency in power numbers is sufficient, all that matters is that the error doesn’t vary. But the ‘error’ in relation to what? How do you know? Most people don’t have the luxury of training with multiple power meters simultaneously. And so unless both torque and cadence are actually measured from within the crank arm and a power number accurately calculated from these two foundational figures, then it’s impossible to know what is correct and what is incorrect. The notion of ‘error’ is totally hollow.
The InfoCrank Road and the soon to be released IC2 have always had genuine measurement as the goal. No algorithms, 4Hz fudges or filling in the blanks on the head unit, just 256Hz of data from each leg, accurate and consistent all the time. For this who are serious about performance, check out the InfoCrank Road and IC2 now. Once you’ve had a taste of what accuracy actually looks like, your training efforts will all start to make sense and there will be no going back. We like to say the truth will set you free, this is certainly true of the InfoCrank and IC2. See you on the trails!
