The article presents the case of a "healthy" 22-year-old male who reported shoulder soreness after playing a bowling game on the Wii. MRI analysis (see article for pictures) revealed "diffuse areas of increased intramuscular T2 signal intensity involving the posterior deltoid, teres minor, triceps, and latissimus dorsi muscles.... [and] nonspecific edema." Sounds painful. As a result, "The patient was diagnosed with acute wiiitis and was treated with rest, nonsteroidal anti-inflammatory drugs, and a lymphedema wrap for his left arm." So how could something like this happen? From the article:
"[L]ittle resistance is offered by the light 200 g handheld controller to the aggressive maneuvers made by the participant, which may lead to awkward deceleration forces being applied to the upper extremity.... It is likely that, during the deceleration phase of swinging the Wii controller, there is significant eccentric loading on the participant’s muscle groups, causing the ultrastructural damage, as demonstrated in this case."
While it may seem absurd that anyone could actually get injured playing Wii Sports, the authors' suggestion that "awkward deceleration forces" may account for the problem appears plausible. I've often felt a mild but distinct shoulder soreness after playing golf or baseball on the Wii, despite the fact that I exercise regularly and stay in pretty good shape. Although I would probably feel pretty sore after swinging a real baseball bat or golf club (things I don't usually do in my spare time), it seems like the lack of natural resistance offered by the Wii remote generates a peculiar kind of strain.
I doubt I'll ever come close to being diagnosed with acute "wiiitis," but I can kind of understand what the article is talking about. Has anyone else experienced unusual soreness related to the Wii remote's lack of resistance?