Anthropometry of Wheeled Mobility Project: Final Report

3.3.15 Reach

3.3.15.1 Forward reach – unobstructed

A large percentage of WhMD users in our study could not reach beyond the most forward point of their WhMDs or foot, and the difference between users of different types of WhMDs was very large (Figure 3‒15). For example, from among the 371 (75%) WhMD users in our study that could perform a reach task, only 78% of the manual chair users, 55% of the power chair users and 48% of the scooter users could reach beyond their mobility device or foot for at least one point between 600 mm (23.6 in.) and 1100 mm (43.3 in.) from the floor. Lower percentages in a forward reach for scooter users partially resulted from having to overcome a greater distance to reach over and/or around the front tiller, particularly at lower heights. Forward reaching capabilities for the three groups declined rapidly for heights above 1200 mm (47.2 in.) and below 600 mm (23.6 in.). Only 32% of our study’s manual wheelchair users, 22% of power chair users and 8% of the scooter users could complete forward reaches beyond the mobility device or foot at heights of 500‒600 mm (19.7‒23.6 in.). The lower limit of the U.S. standard would need to be raised from 380 mm (15 in.) to at least 600 mm (23.6 in.) in order to accommodate over 70%, 50% and 38% of our study’s manual wheelchair users, powered chair users and scooter users, respectively.

Figure 3-15. Forward reach: research findings versus the standard.

3.3.15.2 Side (lateral) reach - unobstructed

For WhMD users in our study that could perform a reach task, over 90% of each of the WhMD user groups could reach beyond the lateral most point of their WhMDs for heights between 800 mm (31.5 in.) and 1400 mm (55 in.) (Figure 3‒16) suggesting a marked improvement over a forward reach. Reach abilities began to drop at 600‒700 mm (23.5‒27.5 in.) and fell dramatically for all WhMD user groups at heights of 500‒600 mm (19.5‒23.5 in.). For heights of 500‒600 mm only 48% of manual wheelchair users, 32% of power wheelchair users and 22% of scooter users could complete a reach beyond the most lateral portion of their WhMD. In order to accommodate over 90% of the manual and powered chair users, and over 80% of the scooter users in our sample, a shift from 380‒1220 mm (15‒48 in.) to 700‒1400 mm (27.5‒55 in.) is needed. The improvement in side reaching performance with increased lower and upper limits as compared to the current standard is likely a function of larger (i.e. higher) WhMDs, and in some cases larger individuals who are now able to use WhMDs.

Figure 3-16. Side reach, unobstructed: research findings versus the standard.

3.3.15.3 Side (lateral) reach – over an obstruction depth of 610 mm

The vast majority of WhMD users in our study that displayed some reach capability could not reach at or beyond a 610 mm (24 in.) obstacle, regardless of height (Figure 3‒17). There were also differences between users of different types of WhMDs. For heights that approximated the U.S. standard of 1170 mm (46 in.), only 31% of the manual wheelchair users, 24% of the power wheelchair users and 13% of the scooter users could reach 610 mm (24 in.) beyond the most lateral point of the WhMD. The results suggest that the recommended maximum depth of 610 mm (24 in.) obstruction would need to be reduced significantly in order to accommodate a majority of our study’s WhMD users.

Figure 3-17. Side reach, beyond a 610 mm obstruction: research findings versus the standard.