Wolf-Thorsten Witt is the founder of the German based training centre www.witt-training.de. He is an expert for wattbased training in road and moutainbiking. In this article he explains us, why using a power meter for training and racing is the most efficient way of riding your bike.
Most bikers do not have an unlimited amount of time for training. Job, family and a lot of different responsibilities as well as the individual time each athlete needs to regenerate, limit the time available for training. Therefore, the remaining time should be used most effectively. The best way to achieve this is using a power meter.
For controlling your effort there are basically three possibilities during your workout.
1. Perceived Exertion (i.e. Borg Scale)
2. Heartrate (i.e. heart rate monitor)
3. Measuring power (i.e. power2max power meter spider)
The perceived exertion depends on various influences and one and the same exercise can feel differently another day. For example: If you take a glass of water in your hand and hold it on a stretched arm, it will feel light at first, but it will feel heavier after a couple of minutes. Still the glass of water has the same weight.
Heartrate is another possibility to control your workouts. The problem with this method is, that power is only measured indirectly. Your cardiovascular system reacts with an increased oxygen transport to your working muscles. This increases your heart rate. Your body needs time to adapt and this process can take more than a minute. Additionally, your heart rate depends on a lot of different processes in your body. For this reason, this method is unprecise. This can lead to athletes not working out effectively.
A power meter shows the exact power for the exact moment in which it is produced. The issues occurring with the other methods do not exist here. A power meter is a direct method to measure your effort.
Here you can see the time lag between heart rate and power. Not only when you start an interval but also after going easy again. The heart rate takes time to adjust to the change.
It is obvious that training and racing with a power meter on an MTB increases the effectiveness significantly. You always have the up to date on your bike computer. You can avoid going to hard or to slow. Pacing yourself during a race is much easier with a power meter and you can controll your own use of energy. As a result, you can also control the calories you have to consume. In a terrain with changing grounds and frequent up and downhill sections, your heart rate is not a reliable performance indicator.
I recommend using a power meter to all my athletes and all of them told me that after using a power meter once, they do not want to go back to anything else.
Have fun with your training!