Categories: Training
Tags: cycling

Cycling power | What every rider should know

September 13, 2017

Yes, anyone can clip into a road bike and pedal around for a while. But if you’re a serious cyclist, chances are your bike is tricked out with all kinds of extras intended to help you reach maximum speed and peak efficiency. So there’s a very good chance your conversations and group texts with your cycling buddies revolve around one word: watts. (Well, watts and, “Where are we stopping for mid-ride muffins?”) Here’s what cyclists should understand about power – and whether or not you should be training with a power meter.

What is cycling power?

There are a lot of hefty terms that get tossed around when you bring power into the cycling game – words like current power, average power, VO2 max, and FTP. And while they’re all important – and helpful – the key thing to understand about cycling power is that it’s how much work you’re outputting while you’re on the bike, and it’s measured in watts (by, of course, a power meter). “Power is the gold standard when it comes to training metrics,” says Anthony Baugh, NASM CPT, PES, CES, and trainer at Independent Training Spot in New York City. “It can seem confusing, but it’s really just the amount of power your legs create while turning the pedals.” While training with a heart-rate monitor is helpful and can tell you how your body is responding to the effort you’re putting out, adding a power meter to your cycling game gives you a more complete look at what’s going on during your ride.

Training with power

The first step when you start training with power is to test your functional threshold power (FTP) so you can establish a baseline by which to base your cycling-specific training zones. “FTP is a theoretical number that is supposed to represent the amount of power you can produce for one full hour,” explains Baugh. “I use the term theoretical because rarely do people do a full hour test of maximum effort due to the stress it puts on the body – and the mind!” You can test your FTP by doing a 20-minute maximum sustained effort test and noting your average power and average heart rate afterward. (You can do this on a bike trainer, or head outside to a fairly flat place where you can ride hard – and without stoplights – for 20 full minutes.)

Once you’ve completed your 20-minute all-out FTP test, multiply the average power by .95, and that’s a close approximation of your FTP. With that information on hand, you can establish your six basic training zones:

  • Zone 1: Active recovery, under 55 percent of your FTP
  • Zone 2: Endurance, 56–75 percent of your FTP
  • Zone 3: Tempo, 76–90 percent of your FTP
  • Zone 4: Lactate threshold, 91–105 percent of your FTP
  • Zone 5: VO2 max, 106–120 percent of your FTP
  • Zone 6: Anaerobic capacity: 121–150 percent of your FTP

“The more accurate the training zones are, the more efficiently you’ll improve,” says Baugh. That’s why it’s important to re-test your FTP every few months to see how you’ve improved and to adjust your training zones.

There are some programs that can estimate power based on your heart rate, weight, age, gender, and other metrics, Baugh says, but those are estimates intended for beginners. “It’s definitely more useful to use rate of perceived exertion as a scale to gauge workouts,” he says. So, he says, if you’re considering a serious go as a cyclist, investing in a power meter is a wise move. (And the Polar M460, Polar V650, and Polar V800 will all sync to your power meter.)

So how does it all actually work?

“Power meters measure the power your legs create with strain gauges and accelerometers,” Baugh says. “Some power meters are single-sided and will measure your power from one leg – usually the left – and then double it to give you your total power. Others will measure both legs individually, giving you more accurate readings, while some measure strain at the power spindle, on the crank arms, on the crank itself, or from the rear wheel hub.”

As for all those terms: watts are a measure of power and VO2 max is a measuring stick for your total oxygen uptake (and can indicate potential ability). The other important number to consider is your weight. “Weight and power are closely related when it comes to a cyclist’s performance,” says Baugh. “Weight is most important for climbers and least important for sprinters. But knowing your power-to-weight ratio is useful when it comes to deciding which races you may want to enter.” Your ability to produce power over different time periods generally dictates the type of cyclist you are, Baugh adds.

In addition to dishing out loads of helpful data, training with a power meter can do pretty much everything except, well, actually doing everything for you. While a power meter helps eliminate the guesswork when it comes to gauging your intensity, can help you identify your weaknesses, and can help you train more specifically for whatever event you have coming up, all those numbers won’t automatically make you a stronger, faster cyclist. You still have to do the work. Mid-ride muffin stops optional.

In the spotlight

Anthony Baugh

Anthony Baugh

Anthony Baugh, NASM CPT, PES, CES, is a Category 3 cyclist and Ironman, and is a trainer at the Independent Training Spot in New York City. He is currently training for the Green Mountain Stage Race in Vermont and the New York City Marathon.