for the National Institute of Health was done by Harvard's medical and public health schools, with input from a Microsoft researcher, that examines how healthy is our posture when we use a tablet, compared to the more traditional desktop or laptop computers.
Needless to say, after examining the stooped, wrinkled posture of 15 tablet users in four different usage scenarios, the researchers concluded that slates are the worst for your back, neck, and so on, compared to a desktop kit, and even to a laptop computer. The four usage scenarios were: a tablet in the users' hands, on the lap in a case, on a table in a case, and on a table in a case, but at a higher angle, suitable for watching movies. The researchers used LED motion sensors to detect the changes in posture. The results:
Head and neck flexion significantly varied across the four configurations and across the two tablets tested. Head and neck flexion angles during tablet use were greater, in general, than angles previously reported for desktop and notebook computing. Postural differences between tablets were driven by case designs, which provided significantly different tilt angles, while postural differences between configurations were driven by gaze and viewing angles. Conclusion: Head and neck posture during tablet computing can be improved by placing the tablet higher to avoid low gaze angles (i.e. on a table rather than on the lap) and through the use of a case that provides optimal viewing angles.
The final recommendation is actually not a very typical way of utilizing your slate - at eye level and in a case that will keep it propped up to avoid unusual neck position, so we'll see what diseases will emerge in the future that orthopedists are already planning to name after tablets.
We had a similar study done recently
as well, but there you have it from another source. Not that we needed further proof how stooping over a 7- or 10-incher for hours at a time is detrimental to the well-being of your vertebrae, but it's nice to have it studied scientifically.