Children as young as 4 are being treated for neck and upper back dysfunction believed to be caused by prolonged use of handheld devices including mobile phones.
Chiropractors are managing an increasing number of patients, including schoolchildren and even preschoolers, for anterior head carriage, says New Zealand Chiropractors' Association spokeswoman Dr Cassandra Fairest.
The condition is where the head is improperly aligned with the neck and shoulders - leaning forward at an unnatural angle.
The greater the angle and length of time the head sits forward of the spine, the more likely a person will experience neck strain, as well as other long-term effects associated with poor posture.
Increased use of handheld technology was a major cause, Fairest said.
"If you observe people when they're using them [devices], their head is almost at a 90-degree angle."
And the problem was growing, she said.
A preschool teacher recently related to her how she noticed children at a daycare centre with "their head ... way forward of their spine".
"You see preschool kids who know how to unlock a phone, they know how to go to ... different apps and use them," Fairest said. "So that gives you an idea of how much time they've spent on the phone."
She recommended parents limit device usage for young children.
"Research shows that ... children under 6, for a lot of reasons, are best not to use handheld devices," Fairest said.
Under Ministry of Health guidelines, children under 2 years old should not be exposed to any screen time and youngsters between the age of 2 and 5 should be limited to less than an hour per day.
"Everybody needs to be vigilant about their screen use," Fairest said.
"Try not to look down at your phone, try to hold your phone up at eye level, because ... if you get a sore arm, it's a reminder that perhaps you've been using it too long. Whereas your neck is a lot harder to sort out long-term."
New Zealanders are spending nearly double the time making calls on mobile phones than five years ago, and mobile internet usage is rocketing.
The average monthly data used per connection is now 2GB, according to the Commerce Commission's latest annual telecommunications report – more than 15 times that of five years ago.
But an increased number of people are seeking treatment for conditions linked to prolonged use of handheld devices.
Hand Institute registered hand therapist Mandy Gumbley said a new problem beginning to emerge was repetitive over-reaching of the thumb, especially with newer larger phones.
She said the joint at the base of the thumb was being overused and overstretched and people with manicured nails were keeping their fingers out straight and using fingerpads to tap the screen, rather than using their fingertip in a flexed position, employing the tendons in the palm of the hand.
"This is overusing the tendons on the back of the hand in an incorrect manner and causing overuse syndromes of the finger extensor tendons."