As the sun sinks slowly behind the stands of the Yarmouk Stadium, it feels a fraction cooler after a day of blistering August heat. Which is just as well, as it is Ramadan and Nader al-Masri, 31, has not eaten or drunk anything since before dawn and will not do so until dusk, still a couple of hours away.
Before that, this quiet, slightly built man will have completed 25 circuits of the stadium in around 45 minutes, concealing the arduousness of the task by his straight-backed but graceful, easy-running style.
It has been a heavy day of Israeli bombardment into Gaza and militant rocket attacks out of it, but his concentration is absolute.
At one point, sprinter Mohammed al-Kousa, 20, falls into step with him, anxious to absorb some of the older distance runner's stamina and strength as he trains; al-Masri seems barely to notice.
For he is on a mission: to cut his 5000m personal best down to the 13m 27s s he needs to qualify for London 2012. Such an achievement would be a sporting emblem, however modest, for the claim to statehood the Palestinians plan to promote by claiming recognition at the United Nations this month.
The problem is one of training facilities. Al-Masri will anyway be eligible for London. Olympic rules permit teams such as the Palestinians to send two swimmers and two athletes even if they do not technically qualify.
And as easily the fastest Palestinian over distance, al-Masri stands to be one of them, as he was in Beijing in 2008.
He comfortably won the first Gaza marathon, in May this year, with a time of 2h 42m 47s.
The course stretches from the northernmost town of Beit Hanoun, where al Masri lives, to Rafah in the south on roads which remained open to traffic, and the the runners had to avoid trucks, donkey carts, potholes and bomb craters.
But as Majed Abu Marahil, 47, another ex-Olympian Gazan and al-Masri's devoted coach, points out, achieving the qualifying time would not only give the athlete the huge satisfaction of knowing he had qualified in his own right, but also bring a bonus for his fellow Palestinian Olympic hopefuls.
"If Nader qualifies we will then be able to send a third team member. And if he can leave Gaza now to train he has a chance of doing it."
And he has virtually none if he has to continue training in Gaza. Yarmouk stadium, built in 1959 when Gaza was under Egyptian rule, was spruced up two years ago by the Hamas authorities in the Strip - but with football rather than athletics in mind.
Turf has been laid on the formerly grassless pitch but the running track round the perimeter is still sand, rather than the all-weather synthetic track virtually every other athlete preparing for the London Olympics will be training on.
"Sand is slower and you are much likelier to get an injury," the athlete explains.
Three years ago, al-Masri was running some 150km a week in a pair of old adidas trainers badly torn from overuse. And while he had saved up enough from the $500 a month he draws as a notional member of the Fatah-dominated, West Bank-run, security forces to buy a new pair, none were available because of the Israeli-imposed blockade.
That problem has now been solved.
But there is nowhere in the territory where he can use the Olympic spikes he was given before Beijing - not in Yarmouk and not on the rubble-strewn open spaces and dusty roads of Gaza where he makes up the rest of his five hours of training a day.
Ideally, he would like to be at a training camp in Palestinian-friendly Qatar which has the kind of facilities you would expect from a leading contender to stage the 2020 Olympics. Al-Masri points out that in 2006 he comfortably beat a Korean rival at the Asian Games - also in Qatar - with his best 5000m time of 14m 24s (the world record is 12m 37s).
"A year later he defeated me; I came back to Gaza after the games and he went to training camp," says al-Masri.
Al-Masri says that when he meets other athletes at international competitions, "they say 'it is good you're running at all. We do camps for six months before any event'."
What is preventing al-Masri from leaving Gaza to prepare is far from clear; on the face of it looks like an all too familiar case of "forgotten Gazai syndrome".
Coach Abu Marahil said he understood that the Palestine Olympics Committee, run from the Palestinian Authority in Ramallah on the West Bank, is having trouble finding the money to pay for a trip.
Not so, insists Jibril Rajoub, once the feared head of Yasser Arafat's security agency, and now president of the Olympics Committee.
He claims the problem is the refusal of Israel to grant exit permits.
It is true that Israel was very slow to give a permit to al-Masri in 2008, allowing him to leave through the Erez crossing - for the West Bank - only in April.
But the Israel Olympics Committee, which says it has already helped to secure movement permits for Palestinian Olympic footballers, said it had no similar request for help to secure such a permit for the Gazan runner.
And Abu Marahil says that anyway, al-Masri could easily leave through the Rafah crossing into Egypt if the support was forthcoming.
Abu Marahil, who is married with three children, and is paid as a member of the Fatah-dominated security services, laments that local Palestinian businesses have tended to sponsor football at the expense of athletics, despite the latter's effectiveness in creating a "a young clean generation who will be able to help us build a state".
Certainly, if anyone deserves a break, it is Nader al-Masri, a role model for the young athletes that Abu Marahil spends much of his time talent-spotting in Gaza schools.
Al-Masri kept up his training through all but the very worst of the warfare - internal as well as with the Israelis - which has dogged Gaza in the past few years. Now London beckons.
"It is my last chance for sure, "he says.