In a sunny temple courtyard in Vietnam, Le Van Thang pushes an iron rod hard against his eye socket and tries to make it bend -- his dizzying strength honed through years of practising centuries-old martial art Thien Mon Dao.

Le Van Thang, 28, student of the centuries-old martial art of Thien Mon Dao, bends a construction rebar against his eye socket inside the Bach Linh temple compound at Du Xa Thuong village in Hanoi
Le Van Thang, 28, student of the centuries-old martial art of Thien Mon Dao, bends a construction rebar against his eye socket inside the Bach Linh temple compound at Du Xa Thuong village in Hanoi AFP / Manan VATSYAYANA

Thang, 28, is one of an increasing number of Vietnamese to find refuge in a sport that grew out of a need to protect the country from invaders, but now offers a route to mental wellbeing in the rapidly changing Communist nation.

Practitioners of Thien Mon Dao have long taken pride in the incredible shows of strength that form part of their routines.

Master Nguyen Khac Phan (front) leads students through a training class in centuries-old martial art Thien Mon Dao inside the Bach Linh temple compound at Du Xa Thuong village in Hanoi
Master Nguyen Khac Phan (front) leads students through a training class in centuries-old martial art Thien Mon Dao inside the Bach Linh temple compound at Du Xa Thuong village in Hanoi AFP / Manan VATSYAYANA

The eye-popping feats include bending metal against their bodies, carrying heavy objects using their throats and lying under the path of motorbikes.

Now many say they also take pleasure from how the sport -- which includes elements of self-defence, kung fu and weapons training -- has steered them on a new course.

A spectator touches an iron bar bent around the head of a student of the centuries-old martial art of Thien Mon Dao at the Hoan Kiem lake in Hanoi
A spectator touches an iron bar bent around the head of a student of the centuries-old martial art of Thien Mon Dao at the Hoan Kiem lake in Hanoi AFP / Manan VATSYAYANA

Thang, a furniture seller who first began practising eight years ago, said he used to get into fights in high school and was also a gambler.

Thien Mon Dao martial arts students practise inside the Bach Linh temple compound at Du Xa Thuong village in Hanoi
Thien Mon Dao martial arts students practise inside the Bach Linh temple compound at Du Xa Thuong village in Hanoi AFP / Manan VATSYAYANA

"Once I stole money from my family but after that, I was brought to Thien Mon Dao by my family and I changed," he told AFP.

"There are so many benefits: I learned how to express my ideas, how to walk properly and behave."

In a sunny temple courtyard in Vietnam, a man pushes an iron rod hard against his eye socket and tries to make it bend -- his dizzying strength honed through years of practising centuries-old martial art Thien Mon Dao.
In a sunny temple courtyard in Vietnam, a man pushes an iron rod hard against his eye socket and tries to make it bend -- his dizzying strength honed through years of practising centuries-old martial art Thien Mon Dao. AFPTV / Quy Le BUI

Thien Mon Dao has roots going back to the 10th century, according to master Nguyen Khac Phan, whose school trains in the complex of an ornate temple on the outskirts of Hanoi. But he says the first official practice of the sport was recorded in the 18th century.

In recent years it's seen a surge in popularity, he adds, with up to three new clubs set up in the capital each year.

Vietnam currently has around 30,000 Thien Mon Dao practitioners across the country, Phan estimates, with occasional public performances helping boost the sport's appeal.

"People come for different purposes but mostly they want to improve their health and mental health," added Phan, who has been teaching the sport since the early 1990s.

"Learning martial arts can help people see life in a better way, improve their strength... give up their mistakes to aim for better things," he said.

From tiny children who have barely started school to people in their eighties, Thien Mon Dao embraces anyone who wants to kick their way up through 18 different levels and seven belts.

"Southeast Asian people think that girls should be gentle and not suitable for learning martial arts," she said. "But I see it differently."