Anyone doubting Henrique Capriles' commitment to a daunting election battle with Venezuela's President Hugo Chavez should take a look at his neck. Or his elbows.

Painful scratches bear witness to the over-excited female supporters who mob the opposition leader during tumultuous stops on his campaign to end nearly 14 years of rule by the South American country's socialist leader.

"Brutal!" Capriles shoots back twice with a smile, when asked in the back of his campaign bus about the personal toll of a presidential bid that has seen him hurtling around Venezuela all year to visit as many cities, towns and villages as possible.

"Look at a photo of me five months ago, and now. The deterioration in the face - it's remarkable."

Capriles has visited about 160 places since the formal launch of his campaign on July 1, diving into crowds, homes, shops and workplaces to try to familiarize voters with his visage and prove his determination to address their problems.

Still taking antibiotics for a recent fever, the 40-year-old Miranda state governor gulps water - then, a bit more discreetly, a Red Bull - after escaping to clamber onto his bus after the first of six campaign rallies on one typical day.

Opening a black bag on the back row of seats reserved for his belongings, Capriles swaps a sweat-sodden shirt and baseball cap for fresh ones, then takes a deep breath to recover his equanimity after an exhausting walk through the town of Guigue.

"There has never been a rhythm like ours, not even in the good times of Carlos Andres Perez or the good times of Chavez," Capriles told Reuters, referring to a charismatic former president and, of course, the incumbent.

SHADES OF CHAVEZ

It was the socialist and populist Chavez who perfected the art of on-the-street campaigning in Venezuela with remarkable nationwide tours that he embarked on between leaving prison in 1994 and winning the presidency in 1998.

Thanks to his emotional connection with the masses, the former coup leader and soldier, jailed for trying to topple Perez in a 1992 coup, came from way behind to beat the establishment's favorite - exactly what Capriles is trying to do now.

This time around, Chavez, now 58, is more limited.

Weakened by three cancer operations in the last year, Chavez has been forced to slow down even though he says he is completely cured. He has, however, discovered a spurt of energy in recent weeks, once again putting on near-daily TV appearances and fronting a dozen major rallies.

Capriles, who is backed by 30 or so parties and groups in the Democratic Unity coalition, generally avoids commenting on Chavez's health. But he plays up the contrast, keeping to his heavy schedule and frequently seeking to depict the president as out-of-touch with the people.

The opposition candidate's projection of zeal and energy plays well with many voters. He often stops to join informal basketball games and walks long distances each day in the course of his campaign visits.

One day he is donning indigenous headgear to meet tribes in the Amazon region, the next talking to farmers in the central plains or mixing with workers at factories.

Journalists and aides struggle to keep up with Capriles, who is affectionately, and increasingly aptly, nicknamed "El Flaquito" ("The Skinny One") by his fans.

"Look at him. He's young, handsome, active, on the street with us," says Dayana Mendez, a 23-year-old student craning for a view of Capriles in Guigue, a small dusty town of bustling streets surrounded by agricultural plains against a backdrop of lush mountains.

"When has Chavez ever been here? He's done nothing in 14 years. He just makes empty promises," she adds, sporting a picture of Capriles on her T-shirt and the same baseball cap, in the national colors, that he normally wears.

POLL CHALLENGE

As energetic as he has been, Capriles still has an uphill battle to catch Chavez by the October 7 election.

The president's welfare policies such as free clinics in the slums and a national economic uptick are behind his enduring popularity with the masses.

Yet Capriles, who is promising to keep the best of Chavez's social programs and presenting himself as a center-left admirer of Brazil's political and economic model, appears to be creeping up.

While most of Venezuela's major, traditional pollsters give Chavez a solid lead of between 10 to 20 points or more, they also show Capriles climbing a few percentage points in the last two months. Two pollsters put him nearly level with Chavez, although the president's camp dismisses them as pro-opposition operations.

"The proliferation of pollsters and hugely divergent poll results mean that the Democratic Unity coalition and the ruling Socialist Party can always find a poll that gives them the result they want," the UK-based LatinNews think tank said.

"What is evident, however, is that Capriles is making a more concerted effort to court voters from right across Venezuela than any previous opposition candidate."

A lawyer by training who grew up in a wealthy family, something Chavez never hesitates to remind voters of, Capriles is particularly targeting pro-government areas on his trips.

That was evident in Guigue, where groups of red-clad "Chavista" loyalists heckled him at several points, chanting "No volveran!" ("They will not return!") in an echo of the rallying cry the president uses to denounce Venezuela's old rulers.

An egg was thrown at Capriles' bus.

"Ha! He's got no chance. He's a traitor who wants to give our oil to the United States," scoffed Ismael Alvarado, a 41-year-old taxi driver leaning on his car as he watched the rally from a side street.

"Look at that: just a few good-for-nothings on his side. If Chavez was here today, then you'd see the whole town out."