On a Friday morning in Cairo, Ahmed Shazly stopped a few cars to allow some 3,000 joggers to cross a near-deserted road in the normally gridlocked metropolis.
Streets that during the week are snarled with exhaust-spewing cars turn almost silent on weekend mornings -- Fridays and Saturdays in Egypt -- as most shops and businesses are closed.
Sport in Egypt used to be mainly practised in clubs reserved for the elite. But now, joggers and cyclists of all backgrounds are using social media to organise group outings across the city.
"The streets belong to us. We can run freely," said 31-year-old jogger Shazly, referring to the slogan of his group "Cairo Runners", which organises runs early on Friday mornings.
Despite the August heat, thousands of joggers gathered at 7am on a recent Friday to start a four-kilometre (two-and-a-half-mile) jog along the Nile on the upmarket island of Zamalek.
Most were young adults in flashy sports attire, with headphones plugged in their ears. Many snapped selfies as soon as they crossed the finish line.
Cairo Runners, founded in late 2012, attracts between 2,000 and 3,000 people every week.
"When you're in a group, even if you're tired, there is a spirit that pushes you to continue," said Karima Hozayen, a 31-year-old freelance translator who runs regularly with a group from her neighbourhood.
Others revel in the absence of traffic. More than three million vehicles are registered in Cairo and its twin province of Giza, according to official figures.
"Oxygen! This is perhaps the only time you can enjoy the empty streets, void of cars," said Hozayen, who wore a loose blue T-shirt, her hair in a ponytail and cheeks still rosy after the workout.
- Why no Cairo marathon? -
In April, 7,500 people took part in its annual half-marathon of 21 kilometres, according to founder Ibrahim Safwat.
Safwat, 32, said he dreams of organising an international marathon "like the one in New York, Paris or Beirut".
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"It's not possible that a city like Cairo, the largest in the Middle East, does not have its own marathon," he said.
A few kilometres away, in the commercial city centre, 60 cyclists took a break on a deserted pedestrian street, surrounded by colonial-era buildings and shuttered stores.
"We try to convey a message: the bike is a means of transport," said Mahmoud Shaalan, 27, a hospital administrator who organises weekly bicycle tours.
A resident of a crowded Cairo neighbourhood, he founded the group Pdal a year ago.
"At first it was between 10 and 15 each time, now we have increased to 80 or 90," he said.
While President Abdel Fattah al-Sisi has called on Egyptians to exchange their cars for bikes -- even leading a bike tour himself -- the dangers of cycling in Cairo are an obstacle to many.
The lack of bike lanes forces riders to cope with the anarchy of the traffic.
But 52-year-old housewife Inas Ahmed has accompanied her 17-year-old son on bike rides for two years.
"I've liked cycling since I was little," she said, smiling. Under her purple and white helmet she wore a hijab -- a headscarf worn by many Muslim women -- along with jogging trousers and a white blouse.
"At first they laughed at me. There were always not so nice comments because I am a woman, and of a certain age, on a bicycle," she said.
"But when you're in the middle of a group, that helps."
Shaalan said some people laugh because they see cycling as a pastime for children.
"But we have to change this culture, to understand that people on bikes have rights on the road, that cycling is a lifestyle," he said.