iPad shoulder - the latest modern life affliction
USING an iPad or other tablet computers can be bad for your shoulders as they encourage people to hunch over the screen, Harvard research suggests.
The millions of people who use the devices, hailed as a bridge between laptops and mobile phones, are also at risk of neck injuries, claims a new study.
Researchers found that the flexibility and convenience tablet computers are hailed for could actually be harming users, especially if held on their laps.
They are at risk of "iPad shoulder" or "iPad neck" because holding a tablet low down means its user has to gaze downwards more sharply, increasing the pressure on their joints.
Scientists say that iPads and other tablet computers should be held higher or placed in a special case that allows them to sit upright on a table, similar to a conventional desktop computer.
The research team, from the prestigious Harvard School of Public Health in the United States, asked 15 people to use an iPad and similar Motorola tablet in a variety of different ways, as well as with and without a special case.
Volunteers held the tablets on their laps with no case, on their laps with the case propping it up and on a table with the case adjusted at to prop it up at a low and high angle.
Researchers measured the users head and neck movements throughout.
Results, published in journal Work, revealed that tablets held in the lap or propped up less caused greater head and neck flexion [bending].
This can in turn lead to neck and shoulder pains in users, although the study authors warned that propping up a tablet too steeply could even put strain on a user's wrists and hands.
Study author Dr Jack Dennerlein said: "Compared to typical desktop computing scenarios, the use of media tablet computers is associated with high head and neck flexion postures, and there may be more of a concern for the development of neck and shoulder discomfort.
"Only when the tablets were used in the table-movie configuration, where the devices were set at their steepest case angle setting and at the greatest horizontal and vertical position, did posture approach neutral.
"This suggests that tablet users should place the tablet higher, on a table rather than a lap, to avoid low gaze angles, and use a case that provides steeper viewing angles. However, steeper angles may be detrimental for continuous input with the hands.
"Further studies examining the effects of tablet and configuration on arm and wrist postures are needed to clarify and complete the postural evaluation."
He added: "Our results will be useful for updating ergonomic computing standards and guidelines for tablet computers.
"These are urgently needed as companies and health care providers weigh options to implement wide-scale adoption of tablet computers for business operations."
Apple sold 15.43 million iPads in the last three-months of last year, compared with 7.3 million for the same period a year earlier.