Tour de France winner Chris Froome has begun a series of physiological tests he hopes can silence those who doubt he is racing clean.
Froome on Monday posted a video on Twitter showing him taking tests at the GlaxoSmithKline Human Performance Lab in London, fulfilling a promise made during the Tour at the height of speculation and innuendo about his performances.
The video came on the same day that Team Sky named Froome as their leader for a second Grand Tour of the season, the Vuelta a Espana which begins on Saturday.
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"Plenty more testing & analysis to be done, I will be sharing results later in the year!"
He also offered a hint of his plans for next season as he posted a picture of him tackling a simulation of the Olympic road race course for next year.
"Replicating possible conditions for @Rio2016_en road race & TT. #RoadtoRio starts here!" he wrote.
Froome promised to take the tests during the Tour as Team Sky sought a way to prove that his performances are not chemically-enhanced, with the hope being that he can show he has a naturally low heart rate.
During the Tour, Froome faced constant questioning from sections of the media and some fans, and at one point he was doused in urine by a spectator while his Sky team-mates also faced attacks, with Richie Porte being punched.
Later this week, Froome will return to the Vuelta, in which he finished second last year, bidding to become the first British winner and only the third man in history to win the Tour and Vuelta in the same season.
He will once again have Geraint Thomas riding in support after the Welshman, who proved invaluable in helping Froome to his second Tour de France crown, was named in the squad alongside Ireland's Nicolas Roche.
The trio were named in the nine-man squad along with Sergio Henao, Mikel Nieve, Vasil Kiryienka, Christian Knees, Ian Boswell and Salvatore Puccio.
When Froome rode to second place in last year's Vuelta, won by Alberto Contador, he was using the race as a comeback event after crashing out of the 2014 Tour on stage five.
This year the race presents an all together different challenge after an already gruelling summer and with a strong field, which includes 2014 Giro d'Italia winner Nairo Quintana, 2014 Tour de France champion Vincenzo Nibali and 2009 Vuelta winner Alejandro Valverde - all of whom also rode this year's Tour.
"I have great memories from this race so I'm pleased to be back," Froome said. "I've had a good rest after the Tour and now I'm ready for my next challenge.
"It will certainly be a very competitive race given the strong field - which will be great for the fans to watch. The competition will be tough and this is bike racing so anything can happen, but we have an excellent team and we're ready to get the race started."
Team Sky principal Sir Dave Brailsford added: "It's been an unforgettable summer for us after winning the Tour de France for the third time, but it's important to move on quickly, realign our goals and focus on the new challenges ahead.
"We've selected a strong squad for the Vuelta that has the right blend of talent and experience to support Chris Froome through the tough three weeks ahead."
The Vuelta begins on Saturday in Puerto Banus, and will finish in Madrid on September 13.