A lot of readers took exception to my suggestion in a recent post (“Estimating Your FTP”) that you could get a very rough gauge of your Functional Threshold Power (FTP) based on several variables, the major one being your body weight. This could prove useful if you wanted to set an FTP goal for your bike training.
Someone pointed out to me that there were also contrary comments on other websites such as SlowTwitch.com. (One guy there threatened to throw away all of my books for writing such an extreme piece.)
A Major Variable to FTP
I realized that as I was reading these comments that several were made by triathletes. It was hard to tell in many cases, but the SlowTwitch comments were more than likely multisporters. That flipped on a light bulb for me, making me aware of yet another major variable that would downgrade someone’s FTP if the guidelines in my original post were followed—time in the saddle.
The less time you ride in a week, on average, the lower your FTP is likely to be. I suspect that if we compared the FTPs of roadies and triathletes, we’d find that for comparable levels of competition within their sports that the roadies would have higher FTPs. I don’t know that for a fact, but I’ve seen something like this happen four times in the last five years with clients and myself. I’ve had three clients who went from multisport racing to bike-only racing for various reasons. In each case the athlete’s FTP increased significantly. The biggest change was for a 50-something male with a couple of decades as a very competitive triathlete who went from 240 Watts at FTP as a triathlete to 280 Watts as a road cyclist—a 17% increase in less than three months. The same sort of thing, only not quite so great a change, happened to me when I had to stop running five years ago due to a knee that didn’t like it any more after nearly 50 years of running. My FTP increased about 20 Watts over the course of a season.
So why do I think this happened for each of these triathletes? More time in the saddle. And, along with that, more hard workouts in a week on the bike.
I would say, based on what I’ve seen in such athletes, the less time you ride in a week the lower your FTP is likely to be. Obviously, if you only ride once a week, no matter what you do the remainder of the days in the week (don’t forget the specificity principle of training), you will have very little improvement in cycling fitness. If you gradually built from one to seven days a week, you could expect a significant change in FTP. Why? More specific cycling-related stress. Stress produces adaptation (ala Hans Selye). Greater stress means more adaptation. More adaptation means more fitness in general including a higher FTP. (There is specific training you can do to improve FTP, which I will get to at a later time.)
FTP for Triathletes vs. Cyclists
Most competitive age-group triathletes ride 3 to 5 times in a week, getting perhaps 6 to 12 hours of saddle time. Serious road cyclists typically ride 6 or 7 times a week with perhaps 12 to 20 hours of butt-on-saddle time. More bike-specific stress. Higher FTP.
So my very rough guess (no science here—strictly opinion) is that if you are a typical triathlete you can subtract in the neighborhood of 10–20% from the FTP you estimated from my previous post and probably come closer to a number that is appropriate for you given all of the other variables. The more you ride the less you’d subtract. If you ride a lot, however, like more than 15 hours a week as many serious Ironman triathletes do, your FTP will be on par with most comparable road cyclists.
I hope no one takes this to mean that I believe triathletes are poor cyclists. This is not intended to be an indictment of triathlon in any way. It’s merely an observation of a key difference between triathletes and road cyclists when it comes to FTP—an observation that needs to be considered when estimating what your FTP could be with more focused training.
On the whole, I think we can figure that a triathlete’s FTP is likely to be lower than that of a road cyclist with everything else being equal—weight, age, gender, body composition, altitude, and experience. To be on par they would have to train the same amount and in the same way.