Bahaa al-Farra will rise early on Thursday morning, pull on his running shoes and Lycra, and join hundreds of others taking part in the second Gaza marathon, spanning the length of the tiny Palestinian enclave.

For many, including around 2,000 children expected to run the course in 1km relays, it is a day of fun, a break in the bleak daily routine of life in Gaza. Others, mainly visitors from abroad, will be making political statements about the continued blockade by Israel.

But for Farra, it's not about fun or politics, but a passion for running which has gripped him for six years and which will reach its highest point so far when the 20-year-old from Gaza City represents Palestine at the London Olympics this summer.

The 10km stretch of the UN-organised Gaza marathon that Farra will run on Thursday will count towards his six hours of daily training, aimed at improving his personal best time for the 400m race in which he will compete in London.

He knows that closing the gap between his record of 49.04 seconds and the 2008 Olympic gold medallist's 43.75 is an impossibility. Instead, he is focusing on the achievement of being Gaza's only participant in the London Olympics and his pride at bearing the Palestinian flag in front of a global audience at the opening ceremony.

"It's a beautiful feeling, both as an athlete and a Palestinian," he said between circuits at Gaza City's Yarmouk football stadium this week. "I will be taking a message from the Palestinians to the greatest games on earth, that Palestine exists despite our difficult circumstances."

Farra will be one of a four-strong Palestinian team, which is eligible to compete in the Games under rules which exempt developing nations from qualifying. The others in the team – two swimmers, including a woman from Bethlehem, and another runner – live in the West Bank.

The young Gazan divides his training between the stadium, the strip's potholed roads, and its long undeveloped beaches. Yarmouk, once a popular venue for political rallies, is shabby and ill-equipped, with an uneven sand running track around the football pitch, rather than the smooth all-weather surfaces on which most Olympic athletes train.

"It's very hard being an athlete in Gaza," he says. "We have no proper stadiums or equipment." The Palestine Athletic Federation, based in Gaza, pays for transport costs and some equipment. But there is no sponsorship, and Farra has no job. His mother struggles to buy and cook the right food for an athlete in training, he says. "It costs a huge amount of money to create a sports hero," he adds.

Farra began running at the age of 14, and gave up school shortly afterwards. Of his seven siblings, one brother has recently joined him on the track, and a sister used to run but stopped as a young teenager to avoid offending Gaza's conservative mores.

He competed abroad twice last year, in the athletics world championships in South Korea and the pan-Arabic championships in the United Arab Emirates. This weekend, he is travelling to Istanbul to take part in the world indoor championships.

Ibrahim Abu Hasaria, who coaches Farra on technique, speed and motivation, has invested heavily in his first Olympic competitor in 12 years as a trainer. "I was also a runner, and now I hope that I can achieve the things I didn't achieve through him," he says.

Also advising the young man is Majad abu Maraheel, 48, the first Palestinian athlete to compete at the Olympic Games, in Atlanta in 1996. "My achievement was to raise the Palestinian flag in front of the world," he says as Farra bounces on the balls of his feet and stretches his muscles.

The 16 days of competition in London fall within the holy month of Ramadan, when Muslims are required to fast from sunrise to sunset. Farra has secured permission from a sheikh to break his fast while training and competing, and will compensate with extra fast days later.

He is excited about visiting the British capital. "I expect it to be a beautiful city, very advanced, completely different from Gaza."

Thursday's marathon will highlight the contrast between the two places. Starting at 7am in the northernmost town of Beit Hanoun, the participants will head to the rutted coastal road, which they will share with cars, tuk-tuks and donkeys. The finishing line is Rafah, the headquarters of Gaza's thriving black market tunnels industry and where the shells of half-demolished apartment blocks from Israeli military incursions still stand. Last year, only nine participants completed the full marathon.