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Coach's Corner
POWER & HEART RATE
What is better for training and racing... Power or Heart Rate?
This question is a hot topic amongst cyclists and triathletes. Each side takes a firm stand on defending their position... somewhat like sticking to one's favorite football team or political party! It doesn't have to be this way. Each one of these training tools has an individual function. They are different and they complement each other. The key is to understand what each one does and how to apply it correctly according to the goal you want to reach.
Here are some key points:
- Simplified, the key to a successful training effect is to apply the correct stress to the correct body system, recover appropriately and let the body adapt. Of course, many variables and factors come into play since each situation and each athlete is different. The job of your coach is to consider all these factors and to put it all together for you so that you can reach your goals... and exceed them!
- In order to create the necessary physiological adaptations, each training session has to be executed at the correct intensity, duration and frequency. Duration and frequency are easy to measure, but the intensity is much harder.
- Intensity is the amount of energy expended to perform a certain task.
- When exercising, the human body engages different systems (cardiovascular, respiratory, metabolic, muscular, phycological, etc), which makes the measurement of intensity even more complex.
Power is measured in Watts per second. Cycling Power measures the energy produced by the muscle and transferred onto the pedals. However, the energy transferred onto the pedals is 25 - 30% of the total muscle energy produced. The rest of this energy is lost as heat. Power training zones are defined by percentages of the FTP (Functional Threshold Power) which is the maximum power the athlete can transfer to the pedals for one hour. Power does not consider internal (other body stresses) or external (environmental conditions) factors, and this makes Power an accurate measurement of pure exercise intensity.
Heart Rate, measured in beats per minute, indicates the intensity of the physiological stress. This is the energy the whole body requires, not only to perform a certain task but also to keep the organs alive, control body temperature, and adjust to dehydration, fuel depletion, internal stresses like illness, fatigue, as well as environmental conditions like cold, heat, humidity, wind, etc.
Heart Rate training zones should be defined based on body oxygenation, fuel utilization and lactate accumulation. Because it considers internal and external factors and the energy the body utilizes to deal with these conditions, it is a better measurement of Total Body Stress.
So, with this said, it is necessary to assess the end goal of the whole training season, each training block and each training session, and determine which measurement takes priority for the specific task.
It is necessary to:
- determine the objective of the training / and or workout
- determine which system will be targeted
- understand the training process to achieve the correct adaptations
- assess the impact internal and external factors have in that particular case
- utilize the correct intensity measurement that will help create the desire adaptations.
There is much more to this particular topic, and you don't have to figure out all these things. Let your coach do that for you!
I thought it would be a good first step to understand what each one of these measurements does, and avoid confusion.
Happy Training
Bettina
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