I finally broke down and decided to get a smart phone for myself. While I find it really useful, I can't help wondering if any research has been done on the "gorilla arm effect" of holding a smart phone at a certain angle while trying to read something or going through an app. It won't be too prevalent if the phone screen is small enough that you can hold it with one hand and click with your thumb but having a smartphone with a large screen (4.3 inches), I can't help wonder what would be the impact as screens keep getting bigger (unless you have large hands).
Here you will find some papers mentioning the "gorilla arm effect". It's a pitty that some of them are not free to download.
Some more articles and references to this syndrome:
The last article defines the Gorilla Arm effect thusly:
So, as long as we keep having "short-term" interactions with our handhelds —or as long as they keep getting lighter—, this will not be a problem. The Gorilla Arm effect though is a nice reminder on how promising interaction patterns can go wrong.