Chris Froome has asked why his performance in leading the Tour de France has invited more scrutiny than any of his rivals' displays in winning other major races.

Froome (Team Sky) leads by three minutes 10 seconds from Nairo Quintana (Movistar) with five stages remaining, four of them in the Alps where the yellow jersey will be won. The race finishes in Paris on Sunday.

The 2013 champion was part of the 'big four' entering the race, but defending champion Vincenzo Nibali (Astana) and Alberto Contador (Tinkoff-Saxo) have endured challenging races and Quintana, runner-up to Froome two years ago, is expected to find his best form in the Alps.

Froome has been subjected to innuendo and interrogations over his dominant win to La Pierre-Saint-Martin on stage 10, when Team Sky colleague Richie Porte was second, 59secs behind, and Quintana third, 1min 04secs adrift, as May's Giro d'Italia winner Contador and, in particular, Nibali struggled.

Rather than assess his rivals' under-par performances, Froome's detractors have focused on his display with some concluding he must be doping. He insists he races clean.

"I've got to admit it is frustrating to an extent that if you look at the last five Grand Tours that have been won by different teams, different riders, there hasn't been the same kind of outcry for power data and numbers and all the rest of it," Froome said.

"Unless I'm missing something. I didn't see the same kind of level of questioning.

"Of course I don't really understand why now it seems to be such a hot topic in this year's Tour de France, given that, okay I won one mountain top finish by 59 seconds. It just seems strange to me."

Host broadcaster France 2 on Sunday broadcast an expert analysing Froome's ascent in the first Pyrenees stage, with Pierre Sallet concluding his power profile of 7.04 watts per kilogram was "abnormally high".

Sir Dave Brailsford is reportedly considering releasing performance data to support his defence of Froome, with the possibility the Team Sky principal may choose to address the ongoing insinuations on Tuesday's rest day.

Brailsford has always stated it is not possible to prove a negative - that Froome is drug free - and has asked for intervention from cycling's world governing body, the UCI.

Such a data release may not be the end of the matter as it could invite more questions than answers for a media and public sceptical after years of drug-riddled performances at the Tour.

"The power data is obviously the intellectual property of the team and if they're happy to give that out then of course I support that, no problems," Froome said.

Froome was asked his weight - used to calculate power - on Monday.

He said: "My weight fluctuates on a daily basis depending on how much fuel I've taken on my fuelling strategy for the day, and also on fluid varying on a daily basis. Anywhere from 67 to 68kg."