The definitive guide on how to best use your power meter, both in training and racing. Co-authored by Hunter Allen, founder of CyclingPeaks Software and noted physiologist Andrew Coggan, Ph.D. This book is the perfect companion to WKO+. Buy Now direct from us to get a signed copy!

Watts per Kilogram: Using the CompuTrainer Indoor Ergometer to Improve Your Performance by Richard Wharton. This e-book contains over 125 pages dedicated to understanding just how powerful you can become with a CompuTrainer as part of your program. The ultimate companion to ERG+, CRS+ and Real3D.

With more and more cyclists using power meters, the need has clearly developed for power-based training programs akin to those used with heart rate monitors. To help meet this demand, built directly into the CyclingPeaks Software program are a series of power-based training levels, or zones. These training levels, which are described here, were developed by drawing upon fundamental principles of exercise physiology as well as approximately two decades of experience with power-based training in both laboratory and field settings. Some of the logic behind the development of this classification scheme is described below.

Basis for system/number of levels: Power at lactate threshold (LT) is the most important physiological determinant of endurance cycling performance, since it integrates VO2max, the percentage of VO2max that can be sustained for a given duration, and cycling efficiency. As such, it is more logical to define training levels relative to an athlete's threshold power, vs., for example, power at VO2max (just as it is more logical to define HR-based training levels relative to threshold HR vs. maximal HR). On the other hand, determining the appropriate number of levels is somewhat arbitrary, since the physiological responses to exercise really fall on a continuum, with one intensity domain simply blending into the next. A compromise must therefore be made between defining more levels, thus better reflecting this fact, and defining fewer levels, for the sake of simplicity. In the present system, seven levels were felt to be the minimum needed to represent the full range of physiological responses and to adequately describe the different types of training required/used to meet the demands of competitive cycling. This table lists the primary physiological adaptations expected to result from training at each level, although these will obviously be influenced by factors such as the initial fitness of the individual, the duration of each workout, the time taken between each interval effort, etc.

Determination of LT power: At least in theory, the most precise way of determining an athlete's power at LT would be to rely on laboratory-based testing with invasive blood sampling. Very few individuals, however, have access to such measurements on a routine basis. Furthermore, while LT is often defined by sports scientists as the initial non-linear increase in lactate with increasing exercise intensity, this intensity tends to be significantly below that which coaches and athletes tend to associate, on the basis of practical experience, with the concept of a "threshold" exercise intensity. Thus, probably the easiest and most direct way of estimating a rider's functional threshold power is to simply rely on data collected in the field using a power meter (see "Threshold power: what is it, why is it important, and how do I measure it?").

HR guidelines: Relating or translating the specified power levels to corresponding HR ranges or zones is somewhat difficult, due to the inherent variability of HR as well as individual differences in the power-HR relationship (even when referenced to threshold power). Nonetheless, approximate HR guidelines have been provided in Table 1, such that they can be used along with power to help guide training if desired.

Perceived exertion (PE) guidelines: The values given are from Borg's 10 point category-ratio scale , not the original 20 point scale that is more commonly used. The category-ratio scale is used because it explicitly recognizes the non-linear response of many physiological variables (e.g., blood and muscle lactate), and thus provides a better indicator of overall effort. Since perceived exertion increases over time even at a constant exercise intensity (power), the suggested values or ranges refer to perceived effort as determined relatively early in a training session/series of intervals.

Other issues: While the system is based on the average power during a workout or interval effort, consideration must also be given to the distribution of power. For example, average power during mass start races typically falls within level 3, but races are often more stressful than training at level 3, due to the greater variability (and therefore higher peaks) in power. Similarly, due to soft-pedaling/coasting, the same average power achieved during a hilly ride or group training session will not reflect the same stress as the same average power achieved during a completely flat ride or solo workout. In part, the variability in power is taken into account in defining the various levels, especially levels 2 and 3 (training at the higher levels will tend to be much more structured, thus limiting variations in power). Furthermore, there is obviously an inverse relationship between power output and the duration that power can be sustained. Thus, it is axiomatic that power during shorter training sessions or efforts will fall towards the higher end of a given range, whereas power during longer sessions or efforts will fall towards the lower end of a given range. Nonetheless, a workout consisting of, for example, 30 min of cycling at level 1 (as warm-up), 60 min of cycling at level 3, and another 30 min of cycling at level 1 (as warm down) would best be described as a tempo training session, even though the overall average power might fall within level 2.

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Increased plasma volume
Increased muscle mitochondrial enzymes
Increased lactate threshold
Increased muscle glycogen storage
Hypertrophy of slow twitch muscle fibers
Increased muscle capillarization
Interconversion of fast twitch muscle fibers (type IIb -> type IIa)
Increased stroke volume/maximal cardiac output
Increased VO2 Max
Increased muscle high engergy phosphate (ATP/PCr) Stores
Increased anaerobic capacity ("lactate tolerance")
Hypertrophy of fast twitch fibers
Increased neuromuscular power