Training by power: Everything you need to know

In 1988, German engineering student Ulrich Schoberer brought to market an invention that changed the face of road cycling forever. The keen amateur cyclist’s game changer nestled in the cranks and would redefine how, at first, the professionals trained and raced, and then, slowly but surely, the amateurs. 

Yes, ladies and gentlemen, we’re talking about the power meter.

Thirty-five years since the SRM (Schoberer Rad-Messtechnik) became a commercial proposition, training by wattage has become the norm for the committed road cyclist. And it’s no longer solely about the SRM. Now you have Stages, Garmin, SRAM, 4iiii… with power meters calculating output at the pedal, the hub… In short, they’re everywhere. And they’re fiscally more accessible than years gone by with models like the Garmin Rally starting from around £400. That said, the SRM, still seen as the gold standard, can still set you back over £3,000 if you go for the Campagnolo version. But what’s three-grand among friends when you’re looking to tame beasts like L’Etape du Tour, the Maratona dles Dolomites or the Fred Whitton Challenge.

Accurate feedback

“That’s fine,” you retort. “I’ve stopped the kids’ pocket money and refused to pay my energy bills; I have the money. But why would I buy a power meter?”

Well, it’s heavily down to a power meter eliminating variables and calculating exact work done, and so delivering data that’s standardised whether you’re facing a headwind, riding downhill or simply cruising on the flat. This differs to a metric like training by heart rate, which essentially tells you how hard you’re working but not how much work you’ve done. It’s also faster to respond than heart rate. This is particularly pronounced with repeated, short, high-intensity efforts that often deliver only a small change in heart rate despite the workload being comparatively high.

Cycling team Israel-PremierTech use TrainingPeaks to improve power (Image by SWPix.com)

As you’ll discover, power meters come into their own when prescribing training sessions and zones for physiological and performance adaptation. You can find out more about the respective zones at the end of this power play. However, having access to a world of wattage data is no use if you don’t have the relevant software to give it some meaning. 

“We’re supported by TrainingPeaks,” says David Bailey, performance consultant at Israel-Premier Tech. As are a high percentage of teams on both the women’s and men’s WorldTours. “It’s probably the best out there right now as it’s evolved over a long time.”

Objective analysis

Delving into the depths of TrainingPeaks is a feature in itself. For the moment, it’s enough to know that key to maximising TrainingPeaks, or the majority of power-based training plans, is to find your functional threshold. Your functional threshold power, or FTP, is the maximum power output you can hold for an hour. Once you’ve discovered this figure, you can hang your training zones off this number like you would if you were training by heart rate. 

Read more: How pro cyclists test their fitness, with UAE Team Emirates

How do you find this figure? Well, according to TrainingPeaks themselves, “You can estimate FTP with your best recent 20-minute power value. Multiply that value by 95% to get your FTP. You can also estimate FTP from a recent best 45-60-minute power output.”

What the end of a 20-minute test feels like (Image by SWPix.com)

A dedicated 20-minute test is common; in fact, Zwift disciples will be well-aware of this test as it’s the standard to calculate your virtual zones. Like online, after a good warm-up, you ride as hard as you can sustain for 20 minutes. For accuracy purposes, you need a quiet stretch of road where it’s unlikely you’ll have to brake due to traffic or road furniture. Once you’ve ridden all-out for 20 minutes, stop the unit, see your average power, subtract 5% and you have your FTP. As a gauge of what figure you can expect, according to website Cycling Analytics, around 49% of their recreational male audience had an FTP below 260 watts while around 46% of females were below 200 watts. 

Just note that there’s a difference between power meters inside and outside, and the more aerodynamic a rider is, the bigger the difference. That’s why it’s useful to spend the time tracking other data like heart rate and cadence to fine tune your outdoor training and race zones within your training. A useful task is to undertake an indoor and FTP test and compare the data as you might require slightly different zones indoor and out. But it’s not essential.

Foundations of a training plan

Okay, you now know your FTP and, by looking at the ‘Welcome to the power zones’ table (below), you can see how your physiology and performance adapts when training at, above or below your FTP. This is vital information to lay the foundations of a training plan. 

Similar to TrainingPeaks, devising training plans are worthy of a feature in their own right. But on a simplistic level, look to increase training workload (volume and intensity) by no more than 10% each week. Do this for three weeks and then see week four as a recovery week where you broadly follow a similar load to week one. From week five, you add 10% to week three’s efforts, then add another 10% for week six and then week seven before the week-eight recovery recoils back to week five’s workload. And so on for how many weeks it is until your goal event.

Hundreds of coaches work with TrainingPeaks and, for a cost, you can download training plans that’ll prescribe daily sessions based on your FTP data. Again on a simplistic level, an easy day tends to follow a hard day while your stamina-boosting long ride takes place at the weekend.

At a deeper level, and using TrainingPeaks as our example, your power data feeds into what’s called the ‘Performance Management Chart’. Back to Bailey for a dig into what this means for you, the recreational rider.

“The Performance Management Chart takes each stress that you have and is a percentage of threshold. It adds that up each day and each week to give you an acute load. Essentially, this is a rolling seven-day average. This aligns with your chronic load, which is your 30-day average. Basically, TrainingPeak’s taken stock-market modelling and applied it to physiological adaptations.”

“On a training camp, the pink line (acute load) rises,” Bailey adds. “This pushes up the blue line (chronic load), too. Also, it features a yellow line. This is the Training Stress Balance, which goes in the opposite direction of the pink line. We use that yellow line to work around peaking and tapering. It’s about replacing fatigue for freshness. It’s a useful tool.” But not without flaws as, Bailey says, it focuses on training stress and doesn’t account for life stress. 

Read more: How to adapt your training as you get older

Still, it gives you a training and physiological insight that takes much of the guesswork out of the effectiveness of your training and helps prevent the committed roadie’s nightmare: overtraining. If the Training Stress Balance drops too low, you could be on the precipice of falling ill and a spell on the sidelines. So, monitoring this line helps keep you on track, as would a supplementary heart rate monitor. You see, a higher or lower heart rate than normal for the same wattage is an indication that something may be wrong. Road cyclists are very driven so can easily not listen enough to our body’s subjective feelings. Having an objective measure using heart rate and power can help us all make smarter choices.

And that is the heart of a power meter’s benefits. It gives you an objective measure to ride smarter in the search for peak progress. But just remember, a power meter is a tool, so ensure you look after it, recharge and recalibrate when needed. Fail to and you lose accuracy. 

Training routes that feature multiple hills are good for building your power (Image by SWPix.com)

One final thing before you scroll through the different power-based training zones and their effectiveness at guiding your rides, you’ll hear a lot about ‘Normalised Power’. This is an adjusted power figure that more accurately reflects the metabolic cost of a ride by discounting periods of cruising. It’s particularly beneficial during highly variable sessions like a route that features multiple hills. 

Okay, that’s power background sorted. It’s time to tap into the benefits of training by power and edge that bit closer to Mr Tadej Pogačar this season…

Welcome to the power zones

American coaches Hunter Allen and Andrew Coggan developed this seven-zone method of training to make the most of each and every ride…