A look at the role training zones (whether based on heart rate, power, or something else) can play in your progress as a triathlete.
This article on training zones originally appeared on Velonews.com. While it’s written specifically for cyclists, it has valuable information that triathletes will appreciate.
As I have become a better cyclist, I have also tried to learn more about physiology and training philosophies. Of course, anybody who looks into training science as it pertains to cycling quickly comes to “training zones” and talk about how, when, and where to spend most of your time. But I’m also someone who doesn’t like to overthink things. So, to continue to improve as a cyclist, do I actually need to use zones?
— Al Dixon
Thanks for your question. It’s true that training zones are ubiquitous in cycling parlance. Almost any time you speak with someone about their training, they’ll start a sentence with, “I was training in zone 2…”
The fact is that zone 2 means many things to many people. That’s because there are many different zone models. None of them is perfect. What they are based on – FTP, VO2max, or power-duration – all have their issues. Nor can any model ever fully account for day-to-day variation within each athlete. All zones are estimates that try to help an athlete understand what’s happening within the human body at any given level of effort. That’s a challenge, particularly because the human body doesn’t have distinct walls between its breaking points.
While there are many zone models based on heart rate, there are actually very few based on power. That’s partially because Dr. Andy Coggan and Hunter Allen came up with a model that’s been the standard. Their system involves not just numbers, but names for each level, which is meant to help users understand what energy system is being targeted at each.
Dr. Coggan’s Classic zone model has seven zones. Another prominent physiologist, Dr. Stephen Seiler, uses a three-zone model. There are many others. Most systems feature zones that are a percentage of VO2max, FTP, or threshold. There are pros and cons to each system; ultimately, all of them have limitations. First, it’s still hard to understand what an individual means by “zone 2”; more importantly, just because you’re training in a particular zone doesn’t mean you’re doing the right training – there are other factors that need to be taken into consideration, including volume.
With all that said, one thing is certain: Training zones can have tremendous value. They provide guidance for training and a means of communicating with your coach or teammates. I reached out to a number of prominent scientists and coaches to get their opinions on training zones. Here’s what they had to say:
Dr. Andy Coggan: “Zones have a lot to do with clarity. They are a system to standardize communication, with the recognition, of course, that physiological responses occur on a continuum, physiological adaptations are a result of a continuum. Nonetheless, humans have difficult dealing with shades of grey, so we paint it as a bit more black and white and say, ‘Yeah, there are seven training levels, because it’s an aid in communicating, especially when dealing with large groups of individuals. But anyone who believes there’s magic in training at a particular intensity, first, they don’t understand how the body responds to exercise. But they also don’t understand what Hunter [Allen] and Stephen [McGregor] and I have been trying to educate people on for the past two decades.”
Colby Pearce: “Zones can provide a useful language. We have to have a common language to discuss intensity with athletes, and I think zones try to assume that language. There are problems with that language, at times. There are three different ways to track what ‘zone’ you’re riding in at any given time… Are you using power? Are you using heart rate? Are you using perceived exertion? Those are three different things. So we have to take all of that into account as well.”
Trevor Connor: “Zones are good for guidance. They’re good for giving a common language. But at the end of the day, if you want to train your best, you’re not going to get there by simply saying, ‘My zone 4 is X watts and I trained in that wattage.’ You have to take responsibility and say, ‘I don’t care that I was supposed to ride at 300 watts, this didn’t feel right today.’ And adjust.
For much more on training zones, listen to episode 72 of the Fast Talk podcast from Velonews.com.