If the remaining competitors in the Abu Dhabi Adventure Challenge thought their 120km crossing of the dunes of the Empty Quarter was the end of being tormented by sand, they had a rude reality check in the race's penultimate cycling section. The Qasr al Sarab team, led by defending champions Richard and Elina Ussher, put in another commanding performance in the 90km mountain bike segment to retain the substantial lead they have held since the start of the six-day race in Abu Dhabi on Friday. But for one of the few times on the race, they actually looked like they had had to dig deep for their lead. Compared to most of the hobbling and sore competitors who stagger across the finish line at each stage of the challenge, one of the world's toughest adventure races, Richard Ussher usually looks as almost as fresh as if he had arrived by car. However after completing a second stage from the Liwa Crescent along roads paralleling the Saudi border yesterday, he looked haggard and drawn, his face coated in sand except for occasional tracks where sweat had washed it away. Along with the remaining 36 teams of the 40 that registered, his four-person team had been assailed by patches of soft sand on the road and exposed skin was literally sandblasted by sand picked up by the billowing head and cross-winds. "It was a pretty tough day at the office," he admitted. He and Elina had biked that section of road in the inaugural Abu Dhabi Adventure Challenge in 2007, which they won, but conditions had changed since then and, like every other competitor, they found it a much tougher segment than they expected. "I think we did this two years ago in two hours and 15 minutes. This year it was three hours and 30 minutes," he said. "Last time I think there was about 400m of soft sand and this year it was about 2km. We ran out of water too." If that 2km of sand had been in one stretch during the 55km second section of yesterday's cycle route, from Qasr al Sarab hotel to a military road near the border, it would not have been so bad. But the sand often came regularly in treacherous patches a few metres wide, threatening to pitch cyclists off their bikes and forcing them to push their bikes through instead. Whenever sand was not present on the road, it was being blasted into them by strong winds. Team Qasr al Sarab added a couple of minutes on to their 26-minute lead over the second placed quartet of New Zealanders, Team Adco, led by Fleur Pawsey. Team Adco's success was in part because they chose fatter tyres inflated at half the usual pressure so they could float better over the sandy patches, but the third-placed French team, Vibram Sport 2000, paid the price yesterday for choosing the opposite option -- thin high-pressure tyres which are faster on the road but much less forgiving in the sand. The result was the gap behind Team Adco roughly tripled from eight minutes to 22 minutes. This time last year Richard and Elina Ussher's team were defending a lead of less than two minutes going into the final day of the adventure challenge, comprising night orienteering and ropework on Jebel Hafeet, the emirate's highest peak, followed by cycling and running through Al Ain. Now they have a comfortable lead, but one that is just one mistake or misstep away from failure, making the final day one for conservative choices about how hard and fast they go. But at least the sand is over.