"So initially my main question was - I wonder how many of these boys do this?"
At the time, Beckett was reviewing a study and noticed one research group that had classified German and South African children as "barefoot" or "shod" using a scored questionnaire.
That prompted him to do the same here in New Zealand - and then ask how many were willing to run on a hard surface, and for how far.
A survey of more than 700 students at the North Shore's Westlake Boys High School found that almost half could be described as "habitually barefoot".
That was in contrast to Germany, where 100 per cent of children wore footwear, and South Africa, where 90 per cent were barefoot.
"This is interesting because until now economic resources might have been considered the primary difference," Francis said.
"New Zealand highlights a culture difference."
Study co-author Dr Lisa Mackay, of AUT's Human Potential Centre, pointed out that being in a higher socio-economic area of Auckland, going barefoot was unlikely to be representative of limited access to resources, but rather a "cultural norm".
"As a mother of two children in New Zealand I am often reminding my kids to put their shoes on before heading out of the house - even in the middle of winter."
Indeed, their study found barefoot wasn't limited to time spent at home, but also during sports and athletics events.
In particular, 59 per cent were barefoot "most of the time" during PE, while nearly half competed barefoot in 100m and 200m athletics events.
At least two of 10 boys also reported they were willing to run 3km in barefeet, despite the hard surface.
"This demonstrates humans innate capability to do this without shoes growing up," Francis said.
There was already plenty of evidence to show there was developmental differences in foot structure when children grew up in shoes.
When it came to running, shoes that contained a cushioned heel allowed the runner to land on the heel of the foot with an extended leg, which might explain why around three-quarters of today's runners were "heel strikers".
This mode of running meant force was being absorbed through the heel, bony structures and joints, with less assistance from muscle.
Francis suggested this might be one of the reasons most running injuries were to structures not designed to absorb force, such as shins, feet and knees.
In contrast, kids who grew up mostly barefoot appeared strong enough to run quickly and for long distances without shoes.
"These New Zealand boys demonstrate the human feet and legs are more than capable of developing the strength for such activities if they are allowed to," Francis said.
"Given the absence of evidence for shoes in injury prevention and the fact transitioning to barefoot is more difficult as an adult - it seems pertinent children spend as much time developing this foot and leg strength as possible.
"What the consequences are for movement proficiency and injury long term we don't know - I would suggest more favourable outcomes in the barefoot children."
