Doctor, I've got iPad shoulder! Using Apple gadget on your lap causes you pain as you hunch over to see screen
Scientists found using tablet computers encouraged poor posture unless it was propped up on a table
Owners of iPads have been warned that using them on their lap can lead to aching shoulders.
For the sudden popularity of tablet computers including the Apple gadget has not allowed for the development of guidelines to 'optimise users’ comfort and well-being', according to the latest research.
A pain in the neck: Using tablet computers like the iPad2 (pictured) knocks posture out of a neutral position
Researchers from Harvard School of Public Health, Microsoft and Brigham and Women’s Hospital found that placing the tablet higher helped cricking the neck, and the use of a case also improved posture.
Study leader Dr Jack Dennerlein from Harvard University, said people flexed their necks more when using media tablets compared to typical desktop computers.
'There may be more of a concern for the development of neck and shoulder discomfort,' he said.
To test this theory, the team asked fifteen experienced tablet users to complete a set of simulated tasks with two media tablets, an Apple iPad2 and a Motorola Xoom.
Each tablet had a case that could be adjusted to prop up or tilt the tablet computer. The Apple Smart Cover allows for tilt angles of 150 and 730 degrees, and the Motorola Portfolio Case allows for tilt angles of 450 and 630 degrees.
Four user configurations were tested: Lap-Hand, where the tablet was placed on the lap; Lap-Case, with the tablet placed on the lap in its case set at the lower angle setting; Table-Case, with the tablet placed on a table with its case at the lower angle; and Table-Movie, with the tablet placed on a table with its case at the higher angle.
A shopper inspects a Motorola Xoom tablet: Tablets only didn't cause strain when they were in Table-Movie configuration
During the experiment, users completed simple computer tasks such as internet browsing and reading, game playing, email reading and responding, and movie watching. Head and neck postures and gaze angle and distance were measured using an infrared three-dimensional motion analysis system.
The bending movement of the head and neck varied significantly across the four configurations and across the two tablets tested.
The iPad2 was associated with more flexed postures when it was placed in its case. This appeared to be driven by differences in case design, which drastically altered the tablet tilt angle and the corresponding viewing angle.
Head and necks were bent more in general when using the tablets than has been reported for desktop or notebook computing.
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,' said Dr Dennerlein.
'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,' he concluded.
The study was published in Work: A Journal of Prevention, Assessment, and Rehabilitation.