Vibration exposure of individuals using wheelchairs over sidewalk surfaces

According to the International Standards Organization 2631-1 standard on human vibration, individuals in a seated position are at risk of injury due to whole-body vibrations when exposed for long periods of time. Wheelchair users fit this description perfectly; however, little research has been conducted to evaluate the amount of vibration transmitted to a wheelchair user. The vibration exposure produced by traversing nine surfaces was evaluated by having 10 individuals without disabilities propel over them in both a manual wheelchair at 1 m/s and a powered wheelchair at 1 and 2 m/s. Root-mean squared (RMS) vertical vibration was examined to determine if differences existed between surfaces. At 1 m/s for both the manual and the powered wheelchair the 8-mm bevel interlocking concrete surface produced significantly higher RMS vertical vibration than the other surfaces. At 2 m/s in the powered wheelchair, the poured concrete surface (control) produced the significantly highest RMS vertical vibration. Based on the manual and power wheelchair results of this study, use of selected ICPI pavers would be acceptable for any route traveled by individuals using wheelchair. Furthermore, a 90° herringbone pattern is preferred over the 45° pattern, and it is recommended that for safety reasons regarding vibration exposure a bevel of less than 6 mm should be used.