It's barely been a year since the last "poo jogger" made headlines in Australia but, like clockwork, another Aussie has been caught doing the gross act.

Celebrity publicist Roxy Jacenko exposed the early morning jogger on Instagram last night, claiming she was repeatedly defecating outside her Sydney office.

The Sweaty Betty founder posted a series of now-deleted videos to her social media, showing the woman appearing to relieve herself on the street earlier that morning and last Thursday.

In one incident, captured by CCTV camera on October 10 just after 6.30am, the blonde woman stops between two parked cars on Watson Street in the inner-eastern suburb of Paddington. Dressed in a pink top and black leggings, she drops her pants and crouches down, holding her phone between her teeth as she does so.

A second video, captured this morning just after 6am, shows the woman jogging down the street on her way to commit the latest unpleasant public act.Jacenko told news.com.au the woman’s disgusting deposits have been multiple times a week for the past four weeks.

RELATED: Why Roxy Jacenko exposed poo jogger

The last person to be exposed doing the head-scratching act was a 64-year-old corporate executive from Brisbane.

In mid-2018, Andrew Douglas Macintosh was charged with creating a public nuisance after neighbours banded together to catch the person they believed had fouled their property multiple times.

They snapped a photograph of him in the act. Holding a piece of toilet paper, he was pictured squatting over a concrete path and looking in the direction of the camera.

But the question everyone was left asking was why someone defecates in public, leaving their excrement on display for all to see.

There are many reasons why people may have the urge to go while running, ranging from gut motility to genetics.

According to a US study of 221 male and female endurance athletes, which was published in the National Library of Medicine Institutes of Health, there was a high prevalence of symptoms directly correlated with a known history of gastrointestinal problems.

Running can also alter something called mucosal permeability, which controls the passing of materials from inside the gastrointestinal tract out to the rest of the body, causing the stool to loosen and impact how often you need to defecate.

This is because of a surge of hormones in your stomach lining from all that bouncing around your body while pounding the pavement.

Royal Melbourne Hospital’s director of gastroenterology Dr Geoff Hebbard told news.com.au certain physical activity and colonic motility were related.

“Vigorous exercise can have significant effect on the gut although that would usually be more than a jog around the block,” he explained.

Perhaps not surprisingly, there’s been little study into the psychology behind why people would choose to poo in public, but Australian psychologist Sandy Rea said that in some unusual cases — although not specifically in Mr Macintosh’s case — it may be to serve a “sexual fantasy”.

“There is paraphiliac disorder, which is characterised by sexual fantasies and sexual gratification,” Ms Rea told news.com.au.

“Somewhere along the line, there’s been a wrong association between sexual fantasy and defecating in public.

“They get a thrill. They get an arousal, but underlying that gratification is anger and a thought disorder.”

Ms Rea said the “thrill” of not being caught can be a reason to push people to continue with the dangerous public act.

“It is a big f**k you, and is where the thought and anger of the disorder comes,” she said.

“The repeat behaviour, and never getting caught, reinstates the ‘I’ll do what I want to do’ mentality.”

Ms Rea said the other reasoning behind “disturbing” public displays could be “elimination disorder”.

“This can occur when the person is really angry at someone or something,” she said. “Perhaps a person or organisation. This is a revenge. The person feels entitled. If I want to do this I can, and I will.”

Mr Macintosh is not the only one to be caught in the act.

In September last year, a woman from Colorado in the US was dubbed the “mad pooper”. When out for her morning jogs, she defecated in front yards, on sidewalks, and even in front of a pharmacy.

And then in the months following, a “serial pooper” attacked a college dorm in the residences of Southern Illinois University.

A report by the university’s student paper, the Daily Egyptian, states that using the laundry facilities was “fraught with peril” because someone was opening the washing machines and applying fecal matter to the interiors.

“I went down into the laundry room to wash my clothes and I opened one of the washers and noticed that it smelled like someone had taken a dump in there,” student Brian Piller told the paper.

“It kind of surprised me,” Pillar said. “I wondered if maybe someone had had an accident in their clothes or something. It never occurred to me that, you know, someone would poop on clothes in the laundry room.”

Clinical psychologist Sharon Chirban of Amplify Wellness and Performance in Boston, told Men’s Health that the act of pooing in public was at the height of “vandalism crime”.

“It’s a statement,” says Chirban. “They’re expressing aggression through an egregious act.”

“As with other vandalising behaviour like tire slashing, graffiti, or salting lawns, the motivation can be anger or envy.

“Maybe the lawn pooper is envious of those in that neighbourhood. Maybe the laundry pooper is angry about the laziness of others to empty washers in a timely fashion.”