Gesture and speech recognition often promise the world a better, more natural way of interacting with computers. Often speech recognition is sold as a solution for RSI stricken computer users. And, for example, prof. Duane Varana, of the Australasian CRC for Interaction Design (ACID) believes his “gesture recognition device [unlike a mouse] will accommodate natural gestures by the user without risking RSI or strain injury”.

Gesturing: A more natural interaction style? (source)

So, it is a fairly tragic side effect of these technologies that they create new risks of physical injury. Using speech recognition may give you voice strain, which some describe as a serious medical condition affecting the vocal chords and caused by improper or excessive use of the voice. Software coders who suffer RSI and switch to speech recognition to code are mentioned as a risk group for voice strain.

Using gesture recognition, or specifically the Nintendo Wii, may cause aching backs, sore shoulders and even a Wii elbow. It comes from prolonged playing of virtual tennis or bowling when gamers appear to actually use neglected muscles for exensive periods of time… In comparison, gamers have previously been known to develop a Nintendo thumb from thumbing a controller’s buttons. I can only say: the Wii concept is working out. It is a workout for users, and it works out commercially as well. I even saw an add on Dutch national TV just the other day. The Wii is going mainstream.

As far as injuries are concerned: If you bowl or play tennis in reality for 8 hours in a row, do you think you will stay free of injury? Just warm up, play sensibly and not the whole night. Nonsense advice for gamers, I know, but do not complain afterward. A collection of Wii injuries (some real, some imanginary):, devoted to Wii trouble.
What injuries do Wii risk?
Bloated Black Eye
Broken TVs, and a hand cut on broken lamp (YouTube, possibly faked).

For more background see also: The Boomer effect: accommodating both aging-related disabilities and computer-related injuries.