I'm sitting at the FCC and being yet another foreigner indulging in my culture – sitting with westerners and looking at the city I’m trying to be part of.

Then I spot a group of about 100 people across the road, next to the river, doing this kind of mish-mash between aerobics, jazzercise and Soviet-style exercise moves with a boom box and instructor leading the show.

It looks like a performance to amuse tourists, but it’s not – locals know that since around 2005 dawn and evening aerobics have become part of Phnom Penh life – an organic growth.

This foreigner had heard about the scene but didn’t realise it is a fairly new one, but is also now a normal part of the culture.

So I crossed the road and joined in. It was a hoot, even though my left leg moved one way when everyone else’s right legs were going the other way.

I was a white man dancing back to front as usual, but after 20 minutes I got into the hang of the groove – and it must be said it was not a particularly frenetic one – and was truly getting into it.

I didn’t realise I was meant to pay 1000 riel to the leader, but he didn’t chase me when I left and went back to the amused German couple watching my bag.

Not so at the Olympic Stadium.

This curiously named place – it has never staged the Olympics but was a public execution venue during the terrible days – is nowhere near the riverfront tourist strip, but is a far more serious stage for Cambodian-style aerobics.

This is the real deal.

At least a couple of thousand people gather here from around 5pm everyday to play football, hard core volleyball – but it’s aerobics which attract the most people for exercise.

They encircle the top of the stadium in around 10 different groups of around 100 each and led by around 10 different instructors who guide the moves of mostly middle aged women who, as one said - “I don’t want to die”- due to the stresses and weight issues affecting their age groups.

Each pays 1000 riel for the hour or so long session. Unlike me.

The curious riverfront foreigner of a few weeks back didn’t join in this time – these practitioners of the public dance/exercise just looked too serious for a pretender to step in line.

But what a great experience.

At the top of the stadium you watch the thousand-plus aerobics people doing different moves depending on the music – from Cambodian hip-hop to more traditional tunes – that the various leaders boom out from their speakers while barking instructions over a microphone.

The music sounds like an aural washing machine to the uninitiated, but it’s obvious the dance followers know the beat of their leaders and follow them.

The trend began after movies and TV shows opened the Cambodian mind to the idea, then the government noticed it and began promoting aerobics as a public health issue.

But it was a trend the government had nothing to do with. It was Cambodian people who took it up.

Phan Nit, a 21-year-old arts college student, took up the daily activity three years ago and is now a veteran of the exercise movement.

“I couldn’t find a better place to get my exercise as there is lot of fresh air here and not too much pollution,’’ she told 7Days during a quick break from her session.

“I want to stay healthy and fit throughout my life, so I try come down here at least three times a week.

“I first found this place when I was out jogging, and while it’s mostly older women who come here I decided I would too. It’s good to be healthy.

“We all get to know each other become friends as well. ”

Meanwhile down the stair teams of young men belt foot balls around a makeshift field while others play a venomous form of volleyball.

Keen crowds gather to watch these games while joggers do rounds of the stadium’s track as if they were Olympic runners in a stadium named after the Games it has never hosted.

It’s a wonderful Phnom Penh experience, one that visitors really should experience if the want an insight into part of what makes the city tick.