Traditional Swiss wrestling, known as "schwingen" in German, has been a male preserve for centuries -- the ultimate test of manhood for Alpine alpha males.

But a growing number of women are trying to muscle their way into Switzerland's top homegrown sport despite opposition from some men.

Schwingen pits two strapping wrestlers in baggy belted breeches against each other.

To win, they must pin their opponent's shoulder blades to the ground in the sawdust ring, with one keeping one hand gripped to the other wrestler's shorts.

While around 6,000 men are registered with schwingen clubs, only 200 women and girls are formally involved in the sport, which is also known as "hosenlupf" or "breeches lifting".

Faced with entrenched male opposition, the women created their own federation in 1992 and went their own way.

But such is the level of overlap -- with men and women using the same judges and venues -- some feel a merger is only a matter of time.

Anne Cardinaux, head of the organising committee of the Romandy wrestling festival in the hills above Lausanne, told AFP that women wrestlers "are still not accepted among the men, not in the same federation.

"But they'll try to get there one day."

- 'King of the schwingers' -

While a few thousand spectators were expected for the men's festival in Romanel-sur-Lausanne, several hundred watched the women's events the day before.

"We are showing off the sport. People who are unaware of it are discovering it," said Brigitte Foulk, spokeswoman for the Romandy Women's Swiss Wrestling Association.

Proudly rural, the amateur sport's heartland is in the German-speaking cantons. But the original handful of women wrestlers in Romandy in the French-speaking west has now swelled to 34.

"It's growing bit-by-bit by word of mouth. Sisters see their brothers wrestling and want to give it a go," Foulk said.

Schwingen may be little known outside Switzerland, but tournaments are shown live on Swiss TV and the top wrestlers are celebrities.

The national festival takes place every three years and draws crowds of more than 50,000, with the winner crowned the "schwingerkonig" -- the king of the schwingers.

- Fair play spirit -

Despite the brute force required to win, schwingen is a convivial sport.

Each bout starts and ends in a handshake, with the winner brushing the sawdust off their opponent's back.

And the prizes are similarly old school. The top one for men is typically a bull.

At Romanel, in a gesture of equality, the women's champion won a pregnant heifer.

"Normally we have lesser prizes. Five years ago we won a jar of honey and everyone was happy," said competitor Franziska Ruch, president of the Federal Women's Wrestling Association.

The Romanel women's festival played out to up-tempo accordion music, occasionally interspersed with live yodelling.

Following bouts, competitors gasped for air in the 32-degree-Celsius (90-degree-Fahrenheit) heat, then dunked their heads in a water trough.

Competitors face six opponents throughout the day.

The five-minute contests take place in a 12-metre wide sawdust ring, scored by three judges, with points totalled up at the end of six bouts to determine who goes through to the finals.

- Changing mentalities -

"It's high concentration and it's also mental. You must prepare," said 18-year-old Antonia Bucher, her face covered in sawdust.

Schwingen is very much a family affair, the apprentice carpenter told AFP. Most women wrestlers "have schwingen family, brothers, fathers or friends who also do this and then they kind of slide into this.

"My friends did it and now I'm doing it," she added.

She acknowledged though that "not everyone accepts" women joining the wrestling ranks.

"The older men think women (should) stay in the kitchen. Not all the time, but often."

Bob Blanchette, one of the senior festival judges, said talks were underway about the national men's federation sharing resources and opportunities with the women.

"There's no reason that women can't participate in it and that the men can't help them to promote the sport," he said.

"It's been a lot of work to change the mentality," he added.

The Romanel grand final saw Isabel Egli triumph after a long battle with her competitor.

The 26-year-old nurse from the central Lucerne region was lifted shoulder-high to applause, then submerged in a pile-on as her Steinhuserberg schwingen clubmates and children charged in.

Posing with her prize heifer, she said she could hardly believe what she had achieved.