Eelke Folmer
University of Nevada, Reno

VI-Tennis: a Vibrotactile/Audio Exergame for Players who are Blind

Lack of physical activity is a serious health concern for individuals who are visually impaired as they have fewer opportunities to engage in physical activities. Especially children with visual impairments exhibit lower performance in motor skills and higher levels of obesity. Barriers to physical activity they encounter include: (1) lack of exercise partners or sighted guides with whom to exercise; and (2) fear of injury while exercising.

Exergames are video games that use physical activity as input. When compared with regular physical activities, exergames have some attractive properties for individuals with visual impairments because: (1) exergames can be played independently and do not require an exercise partner or sighted guide to be present; and (2) exergames are performed in place, which minimizes the risk of injury. Exergames are not accessible to users with visual impairments. Because exergames simulate real physical activities they involve spatial-temporal challenges (hand-eye coordination) that rely upon the visual sense. The type and direction of the gesture that players need to provide, such as kicks, punches, steps or swings, and when to provide the gesture are typically indicated in the game using visual cues. This project explores how to make a tennis based exergame accessible to blind users.

How it works

VI Tennis implements the gameplay of a popular commercial tennis exergame (Wii Sports Tennis) that is played with a motion-sensing controller called a Wii remote. Wii Sports Tennis only involves a temporal challenge, e.g., when the ball gets close, the player has a few seconds to provide the upper-body gesture (swing their Wii remote from back to forward like a tennis racket) to return the ball. There is no spatial challenge as the computer automatically moves each player to the location of the ball. VI Tennis implements the same audio feedback as Wii Sports Tennis and although the player, with practice, can estimate when to provide input using the sounds of the ball bouncing, supplemental representations of the location of the ball were explored. Preliminary trials showed that extra audio (sonification) to convey the ball's location interfered with existing audio, and instead the vibrotactile capabilities of the Wii remote were explored. A 250ms vibrotactile cue (250hz) indicates the bouncing of the ball to indicate to the player to prepare for returning the ball, and a 2000ms cue indicates the time frame in which the player must provide their gesture. A user study at a sportscamp for blind children (Camp abilities) found VI Tennis to engage kids into levels of physical activity that were high enough to be healthy.


This game can be downloaded from our VI Fit website. All you need is a $15 Wii remote and a bluetooth compatible PC.


Child playing VI Tennis
A blind child playing VI Tennis.


Tony Morelli, John Foley, Luis Columna, Lauren Lieberman, Eelke Folmer. VI-Tennis: a Vibrotactile/Audio Exergame for Players who are Visually Impaired, Proceedings of Foundations of Digital Interactive Games (FDG'10), Pages 147-154, Monterey, California, June 2010. [34% acceptance rate]