If you are good at weightlifting in Iran, you can become as rich as a Premier League footballer. The country boasts 300 professional weightlifters, dedicated arenas in every sizable town, and full-time officials in all 31 provinces. When an Olympic champion got married in 2006, his wedding made national television news.

“Weightlifting is more popular in Iran than in any other country,” said Mohammad Barkhah, the national team’s head coach. Only football is more popular and, as with football, the sport has historically been an overwhelmingly male domain – until now. Next month four teenagers are set to become the first female weightlifters to represent Iran – in a competition in Uzbekistan. The young women have the 2020 Olympic Games in Tokyo in their sights, and weightlifting has become an unlikely vehicle of female empowerment.

The change has come about thanks in part to a remarkable alliance between Iran and the US, and the efforts of an eight-year-old girl who won nationwide support for the women’s cause last weekend.

Aysan Adib was in tears when security men enforced a ban on females entering the arena for a men’s international competition, the Fajr Cup, in Ahvaz, south-west Iran. Religious leaders in Khuzestan province had given permission for the ban to be relaxed, but because the signed paperwork was not presented the security guards refused them entry. Aysan, and six-year-old Yeganeh Bandeh Khodo, thus missed a unique chance to show off their skills in a demonstration scheduled for the penultimate day of the event.

The result was a passionate protest that rapidly went viral. Ursula Garza Papandrea, one of the most senior women in the sport, who headed a US delegation of three to the competition, joined the exiled girls outside in protest.

The Americans were in Ahvaz to help launch Iran’s female weightlifting programme, making sporting history along the way. Garza Papandrea, a highly qualified coach who is president of USA Weightlifting and vice-president of the sport’s global governing body, the International Weightlifting Federation, became the first woman to coach a man in an Iranian competition when she helped Derrick Johnson to victory in the Fajr Cup 62kg class on the first day. US technical official Sally Van de Water, who is also state folklorist for Pennsylvania, was the first woman to referee in a men’s competition.

The Americans have forged a strong relationship with Iran – “this is above politics,” said Garza Papandrea. They were feted by dignitaries everywhere they went, photographed, interviewed and plied with gifts. The exclusion of the two girls was therefore embarrassing for Iran – and big news.

Ursula Garza Papandrea and Sally Van de Water join Aysan Adib outside the Fajr Cup venue. Photograph: Brian Oliver

That news spread fast after pictures of a tearful Aysan appeared on social media. Khuzestan’s provincial governor, Gholamreza Shariati, stepped in, and a day later led Aysan, Yeganeh and the vice-president of Iran’s women’s weightlifting programme, Reyhaneh Tarighat, into the arena. There were also women among the spectators, on the results and media desks and, to the visible disgust of one of the security men, even in the VIP seats. Aysan and Yeganeh gave their performance a day late, when the men had finished. As the crowd cheered they became the first female weightlifters to appear on Iranian television, live on state-owned Channel 3, after which they were surrounded by media men and – another first – women.

The story made the front page of national daily newspaper Hamshahri, which has nearly a million readers. A call to “let them in” went up as the issue of women in sport became a hot topic in the Iranian media.

Shahrokh Shahnazi, secretary general of Iran’s Olympic committee, said the body would be supporting the women and could one day bid to host the weightlifting world championships, which have not been held in Iran in more than half a century.

Of all the many women’s projects I have supported over the years, this one is the most significant Ursula Garza Papandrea

The brains behind the women’s programme is Ali Moradi, influential president of the Iranian weightlifting federation. He became convinced of the need for change at the 2016 Rio Olympics as he watched a teenager in a hijab, Sara Ahmed, become the first Egyptian woman to win an Olympic weightlifting medal.

“We cannot make any progress without the support of men,” said Tarighat, who has “a vision that in the future we will become even better than the men’s team”.

Big challenges remain. Women’s sport is barely ever shown on television in Iran, and women are still forbidden to watch men compete, may not perform without a hijab, and their kit must conform to Islamic dress code. A newly designed weightlifting costume was sent to the authorities last Monday: a verdict is due soon.

Iran’s top female footballer, Niloufar Ardalan, was unable to play international matches in 2015 when her husband would not give the approval she needed, under Islamic law, to travel to games outside Iran. She contacted Garza Papandrea to thank her for her support in weightlifting, and said she wished somebody would do the same in football.

“There are issues in sport and gender that are experienced only in Iran,” said Bahman Baktiari, an American-Iranian academic who is executive director of the International Foundation for Civil Society. He added: “Islamic restrictions take away the competitiveness of sport in Iran.”

Garza Papandrea, who is also a lecturer in political science in Austin, Texas, said she had been blown away by the reaction: “Of all the many women’s projects I have supported over the years, this one is the most significant.”

She and Van de Water wore headscarves for their week in Ahvaz. “I’ll wear whatever we have to wear, anywhere, if it will help to further women’s weightlifting – and I don’t think that is true of all the feminists in our sport,” she said. “We’re talking about developing a long-term relationship with Iran. If we can help Iranian women to compete internationally, of course we want to help. I’m so proud to see what is happening here.”