Adapted with permission of VeloPress from Run with Power: The Complete Guide to Power Meters for Running by Jim Vance
If you’re a triathlete, a bicycle racer, or a fan of either pro sport, you are probably already familiar with the use of power meters in cycling. The power meter transformed training and racing in the cycling world. It has surpassed every other training tool because it delivers an objective and repeatable assessment of overall fitness without any of the drawbacks of previous measurement methods, such as heart rate, speed, and perceived exertion.
In fact, the advantages of the cycling power meter are so great—and the margin of error so small in the world of competitive cycling and triathlon—that to ignore the information and the advantage from a power meter would be to concede victory before the race had started.
In the running world, we have recently seen a surge in the popularity of GPS units whose main advances are mapping your route and elevation gain/loss and displaying pace, which is a measure of how long it takes to cover a unit of distance (minutes per mile). The increased adoption of GPS shows that the running world, like the cycling world, is open to embracing technology and its benefits.
While the GPS unit is a useful tool, its contribution to training pales in comparison with the advantages the power meter can provide. The leap in technology is something like the difference between using a typewriter and a computer. In the history of running technology, a stopwatch is probably equivalent to using a typewriter—pretty good at its job, but severely limited in scope. Running’s step up to heart rate monitors was a revelation, but in retrospect, it was like moving from the typewriter to what we would now regard as an old, heavy, slow desktop computer. Today’s GPS wrist units are like the first cellphones, much like a flip-phone. The portable power meter for running is the next step, equivalent to the laptop, tablet, and smartphone coming into existence all at once. And while you can still accomplish a lot with a desktop computer, you likely will be much more effective in many ways if you add the laptop, tablet, and smartphone to your arsenal. This is what the power meter brings to the world of training and racing for competitive running.
In this post, we’ll take a look at three ways cycling and running power meters are different.
#5: Cyclists Like Big Watts, Runners Want High Speed per Watt
Cycling power and cycling FTP differ from running and rFTPw. Cyclists want to get their wattage numbers up, as the power meter on the bike measures the watts directly applied to moving the bike forward. When cyclists fatigue, their watts decrease because they can no longer produce power to move the bike forward as effectively as before. If a cyclist saw her watts increase even as she fatigued, she would be pretty excited!
Running power meters are different because they give the work rate that is being done by the body in two or three planes, depending on the power meter, not specifically what is being used effectively and applied to running forward. In Chapter 5 of Run with Power, we discuss how to use the power meter to gauge how efficient you are at producing speed per the watts you’re generating.
#6: In Running, Efficiency Index Replaces Normalized Graded Pace and Normalized Power
Before power meters for running, there was no way to measure your speed per watt of effort. Now Efficiency Index (EI) is probably the best metric for monitoring your speed produced per watt.
EI = Avg Speed (in meters per minute) / Avg Power (in watts)
Some users—especially those with experience of using power in cycling—might think this calculation should instead compare Normalized Graded Pace and Normalized Power. If you usually train on the same courses, and they are loops (you finish where you started), there is little reason to normalize the pace and the power since uphills will be matched by downhills, and vice versa.
Also, unlike cycling, there is no coasting in running, nor a way to tuck into a pack of runners and draft to reduce watts by 50 percent or more, compared with being on the front. Generally speaking, there is nowhere near the variance of power outputs among runners in a race or training session, compared with cyclists.
#7 Easy Running Is Harder than Easy Cycling
Running uses such large groups of muscles that the range between easy and threshold watts is not as great as in cycling power zones.
The easiest Cycling Power Zone (Zone 1) for easy spinning is <55% of FTP while Zone 2 for Aerobic Endurance is 56-75% of FTP.
The easiest Running Power Zone starts at <81% of rFTPw! Zone 2 for running is 81-88% of rFTPw.
See this post for Jim Vance’s Running Power Zones.
RUN WITH POWER is the groundbreaking guide you need to tap the true potential of your running power meter like SHFT, Stryd, or RPM2. From 5K to ultramarathon, a power meter can make you faster—but only if you know how to use it. Just viewing your numbers is not enough; you can only become a faster, stronger, more efficient runner when you know what your key numbers mean for your workouts, races, and your season-long training. In Run with Power, TrainingBible coach Jim Vance offers the comprehensive guide you need to find the speed you want.
Run with Power is available now from your local bookstore, tri or running shop, and from these online retailers:
Coach Jim Vance
Limited offers: Get Run with Power FREE with purchase of a SHFT, RPM2, or Stryd power meter while supplies last.