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…

Cycling Plus - - POWER - Words James Witts Pho­tog­ra­phy Getty

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.”

Power pack­age

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...

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