Anthropometry of Wheeled Mobility Project: Final Report

3.3.16 Door Use

A total of 144 WhMD users completed door use tasks for at least one of the doors. In some cases, WhMD users were not able to complete tasks involving other doors due to scheduling issues (i.e., lack of time) and building renovations.

The differences in the sub-sample composition compared to the overall sample on demographic and anthropometric variables were generally small. Table 3‒5 summarizes the descriptive statistics for the sub-sample. The sub-sample was on average younger than the overall sample (see Table 3‒2). The differences in age are not unexpected since latter data collection efforts in Ithaca and in Buffalo involved targeting older adults who were not measured at the IDeA Center and therefore could not complete the door use tasks. Differences between the gender composition, occupied width, occupied length and maximum power grip strength were fairly modest. For example, the mean occupied width of the sub-sample was 10 mm (0.4 in.) less than the occupied width of the overall sample, and the occupied length of the sub-sample was only 6 mm (0.2 in.) less than the overall sample (See Figures 3‒3 and 3‒4).

Table 3-5. Descriptive statistics for the sub-sample that completed the door use tasks.

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The “Opening Maneuver” and “Operating Latch” door use tasks posed difficulties for very few WhMD users, requiring “minimal effort” for more than 85% of the trials (Table 3‒6 a-b). Door use tasks that were found to present WhMD users with difficulty were “Opening”, “Through Passage”, “Closing Maneuver” and “Closing”. For these tasks, a significant percentage of trials were rated at “maximal effort” or “impossible” for at least one of the three doors (Table 3‒6 c-f).

WhMD users had more difficulty “Opening” door 3, as compared to doors 1 and 2. Fifty-two percent of the pushing trials were rated at “maximal effort” or “impossible” for door 3, as compared to 12% for door 1 and 9% for door 2 (Table 3‒6 c). Forty percent of the pulling trials were rated at “maximal effort” or “impossible” for door 3, as compared to 13% for door 1and 27% for door 2. The additional effort required of door 3 for the “Opening” task was expected because door 3 had a mechanical closer that had a resistance of 7‒8 lb-f.

A higher percentage of WhMD users also had greater difficulty with “Through Passage” for door 3 than doors 1 and 2. Forty-four percent of the pushing trials were rated at “maximal effort” or “impossible” for door 3, as compared to 11% for door 1 and 6% for door 2 (Table 3‒6 d). Eighteen percent of the pulling trials were rated at “maximal effort” or “impossible” for door 3, as compared to 14% for door 1 and 11% for door 2. This was expected because of the closer and also because door 3 had a 6 mm (1/4 in.) threshold, and was the narrowest of the three doors (755 mm or 29.75 in.). The door most often rated as requiring “minimal effort” was door 2. It did not have a closer or threshold and was the widest (1040 mm or 41 in.). The presence of the closer requires the user to continue to apply pressure to the door while passing through the opening.

The “Closing Maneuver” presented problems to WhMD users for each of the 3 doors studied. “Closing Maneuver” was rated at “maximal effort” or “impossible” for 36%, 26% and 100% of the pushing trials and 57%, 42%, and 100% of the pulling trials for doors 1, 2 and 3, respectively (Table 3‒6 e). However, the very high number of “blocked view” trials for door 3 (103 for pushing and 100 for pulling) is worth noting. Trials for this door were often not observable when the participant successfully passed through the door to the space beyond because the mechanical closer closed the door while the researcher remained on the side of the door where the trial started. Most, if not all, of these trials would have required minimal effort. If the “blocked view” trials for door 3 were categorized as either “minimal” or “moderate” effort, then only small percentage of the trials (19% for pushing) and (4% for pulling) would have been rated as “maximal effort” or “impossible” for the “Closing Maneuver).

Similar results were found for the “Closing” task, although this task was the one likely to be rated as “maximal effort” or “impossible” (Table 3‒6 f). One interesting finding, however, was that “Closing” trials were more likely to be rated as “minimum effort” for door 2 than door 1, despite door 2 being 215 mm (8.5 in.) wider than door 1. The difference in rating was therefore more likely to have been influenced by the latch side clearance than door size, especially on the pull side. Door 1 only had a 76 mm (3 in.) latch side clearance.

Differences in observed ratings of effort were also found between different device types for some of the door use tasks. For example, “Closing” trials involving scooter users were more likely to be rated “minimum effort” than trials involving manual or powered chairs for doors 1 and 2 (Table 3‒7 a, b). This may be because scooter users in general have greater upper extremity function and strength and can more easily close doors than those who use manual or powered wheelchairs.