Every WorldTour team, including Sky and Movistar, uses power meters. Why? It’s all down to taking the guesswork out of peaking, which is why they’re just as popular with recreational riders…
One of the abiding memories of the 2017 Tour de France is Chris Froome ascending at speed with his nodding head diverting from what lies ahead to what lies below. Instead of eyeing the road, the 32-year-old Brit honed in on data emanating from his Garmin bike computer, which received a constant stream of wireless information from his Stages power meter.
Racing by numbers has been a highprofile feature of the Tour since 2012 when Sir Bradley Wiggins and his Sky ‘entourage’, including Froome and Richie Porte, strangled the life out of the opposition by basing key climbs on specific, sustainable wattages. This wasn’t ‘panache’, this was clinical racing and pacing – and it worked.
Cycling artisans argue that power meters have made racing boring; that they’ve suppressed instinct and killed the romance. Others disagree. “Power meters have refined how riders train and they’re no longer flogged like they used to be,” says Chris Boardman. “I love the idea of training and racing by feel but, in the most part, those days are numbered.”
Born in Germany
Although cycling by wattage appears to be a recent phenomenon, the first commercially available power meter hit the market back in 1988. German engineering student Ulrich Schoberer, a keen cyclist, realised feedback metrics like heart rate, cadence and speed were inefficient as they could be affected by variables like wind direction, temperature and terrain. Power output isn’t, and he set about designing and manufacturing the SRM.
Schoberer recognised that to accurately calculate the power output of the cyclist, the gauge would have to be as close to the foot’s contact point as possible. That’s why he integrated his SRM into the cranks. Though not the lightest on the market, it remains the standard for measuring riders’ power output.
In 2017, SRM provided power metrics for eight of the 18 WorldTour teams including Romain Bardet’s AG2R La Mondiale and
rode at 332 watts for 19.34 minutes. But it was the last 3km of the climb when the stage erupted thanks to Fabio Aru’s attack. Out of the saddle but composed, Uran held onto Aru thanks to a 1:27-minute effort at 412 watts, hitting a devilish maximum of 666 watts – a huge 10.57 w/kg. Over 8:12 minutes, Uran generated 378 watts to counter the Italian’s break.
Come the 13.2km descent, Uran averaged 59.2kph, hitting a maximum speed of 84.3kph on the slippery roads before arriving at the final 1km. Here, Uran’s power output rose from 463 watts to a peak of 1025 watts. That and his tactical acumen gave the 30-year-old the stage victory.
Training speed, power, strength…
All those numbers are enough to unsettle Rachel Riley, but they do have practical meaning, which all comes back to efficient training. Daniel Healey is one of the world’s finest cycling coaches and former head of sports science at Tinkoff. He now runs his own coaching company. “I’ve been using SRMs since the mid-’90s,” says the New Zealander. “They’ve transformed how you ride and that’s heavily down to training zones.”
Like training by heart rate, power zones relate to specific physiological adaptations [see page 13]. “I’ll give you an example of how zones work,” explains Healey. “In December, for a guy like Alberto [Contador], we were already building for July’s Tour. By that I mean we were making him fit and then strong, but not doing too much power work or high intensity. What we know with confidence is that training within certain training zones will produce a series of physiological modifications that’ll set up a rider like Alberto for a long and successful season.”
During December, the aim is to build a strong base that’ll lay the foundations for more intense work once the race season approaches – which is as early as January and the Tour Down Under for many riders. The early-season modifications Healey alluded to primarily focus on improving a rider’s capacity to transport and utilise oxygen – nectar when it comes to ultraendurance events like the Tour de France.
These adaptations are numerous but five of the most significant are: increasing the number of mitochondria in the exercising muscles; increasing the size and number of muscle capillaries; increasing haemoglobin and blood plasma levels to enhance oxygen transport; better thermoregulation due to increased plasma volume and improved circulation; and greater glycogen storage, which becomes useful for higher-intensity race efforts down the line.
“To achieve this, we’d instruct our riders to target recovery or high tempo wattages [but still relatively low intensity] for most of November and December,” adds Healey.
Setting a benchmark
Which is all well and good, but how do Healey and others set training zones like Recovery and Tempo?
“We would test every rider to not only see if their fitness is improving, but also to set their individual training zones,” he says. “To set each zone, we need a centrepiece to work from – aka the ‘threshold’. This is the maximum power you can hold for one hour, though that can be tiring and affect the gains you’re looking for in subsequent training sessions, so we tend to feature this at the end of training camps and keep it to 20 minutes. With that number, we slice off 5 per cent to give an hour’s prediction and a threshold figure.”
The reason threshold is chosen as the benchmark by which all other zones are set is because it’s the most important physiological determinant of endurance cycling performance, since it integrates three key variables: VO max, the 2 percentage of VO max that can be 2 sustained for a given duration and cycling efficiency.
“Threshold is the point where you’re consuming as much lactic acid as you’re producing,” adds Healey. “You can recycle
Daniel Healey “We would test every rider to not only see if their fitness is improving, but also to set their individual training zones”
much of it and sit on that uncomfortable level for a long time. Above that and lactate starts to accumulate, and that’s where we hit the red zones, or VO zone. There’s only 2 so much work you should do in those and you should only do that work in controlled doses, though essentially the higher the threshold, the stronger the rider.”
A professional rider’s functional threshold [functional threshold and threshold are interchangeable terms when it comes to power] is a guarded secret, though Sir Bradley was reported to have had a functional threshold of between 440-460 watts, which helped him sustain the pace to smash the Hour Record. A good recreational rider would be below 250 watts.
Once each rider’s individual zones have been calculated, it’s common for the coaches to print out the zones on a piece of card and stick them to the stem of the rider’s bike. “That’s something I do,” says Healey. “There’s a grey line running right across the middle of the card and that’s where threshold sits. During early winter, for instance, we’d tell the riders to train below that middle line. If they go over it, it’s not the adaptation we’re after.”
The rise in power meter use has conjured up huge amounts of data with analysing and coaching software TrainingPeaks the professional package for many. It’s used by BMC Racing and Cannondale-Drapac, with riders uploading their ride data for dissection. The results dictate the intensity and duration of subsequent sessions. You can also compare this day-by-day, week-by-week… to see if the training is having the desired effect – to race longer and faster. Probably the greatest development has been in managing fatigue and form to peak for races, but its key sell is flexibility.
“There’s no one proper way to use our system,” says founder Dirk Friel. “Each team and each coach has a different methodology and their own metrics and data points that they’re looking at each day. For some teams, a coach will be looking at each individual stage file of the Tour and gaining feedback. Did the rider hit any peak power values today? How hard was the stage? What was the stress score of the day? Are they at a fatigue level where they can perform five days from now at the major climbs?”
Though TrainingPeaks is the software used by many teams, it’s not the only one. Sky now uses Today’s Plan, while BMC sports scientist David Bailey flags up a programme called Golden Cheetah that he sees as equally impressive. “It’s been developed by MIT graduate and top physiologist Phil Skiba,” he says. “He got a load of guys to exercise in an MRI and examined the depletion of phosphates. With that data, he created a mathematical model that helped to devise training zones for all riders – without them having to have an MRI scan.”
Whether teams remain with TrainingPeaks, leap onto Golden Cheetah or choose some other power-based software, the fact coaches can calculate the wattages needed to win certain stages, lead over the stiffest of climbs or create a breakaway means they can take the guesswork out of racing. They have a goal figure. They ‘just’ need to design the right training sessions, manage fatigue and consume the most appropriate nutrition (which TrainingPeaks and power data can help with, too). Ultimately, power meters and respective software will always have their critics but they guarantee the professionals, and recreational riders, race and train smart. Whether they race ‘romantically’ depends on your cycling sensibilities…
Dirk Friel “Each team and each coach has a different methodology and their own metrics and data points that they’re looking at each day”
Above Fabio Aru relies on Power2Max meters to reveal his numbers Right Alberto Contador and his Trek team favour SRM units
Top right Above For accurate results, the gauge needs to be as close to the contact point as possible Team Sky’s Chris Froome in what has become a familiar headdown position Far right Right Love them or hate them, power meters provide valuable data...