Examining perceptions of existing and newly created accessibility symbols.

BACKGROUND: Symbols are used to convey messages in a clear, understandable manner, without the use of written language. The most widely recognized symbol used to denote access for persons with disabilities is the International Symbol of Access. This symbol has been criticized for its inadequate representation of disability diversity poorly representing universal design of space and products. OBJECTIVE: This descriptive study explored individual comprehension and perceptions of nine existing and newly created accessibility pictograph symbols and identified one that represented universal access to fitness equipment. METHODS: A survey was disseminated electronically and face-to-face to individuals, groups and organizations affiliated with inclusive fitness equipment, space and programming. Quantitative data was analyzed for descriptive statistics, rank order of symbols and group comparisons of rankings. Thematic analysis of open-ended question results revealed themes to enhance understanding of symbol rank order. RESULTS: 981 participants completed the survey. Symbol four, shaped as a Venn diagram containing three icons representing individuals with varying ability levels, was ranked highest with no significant differences in group comparisons between participants with and without a disability and U.S. residents versus non-U.S. residents. 85.4% of participants demonstrated accurate comprehension of this symbol. Though symbol five had the same symbol rank median value, this symbol's distribution of scores was lower. CONCLUSIONS: Participants accurately comprehended symbol four and it was identified as the highest ranked symbol representing universal access to fitness equipment. Because of symbol unfamiliarity, adoption will require education and consistency of use and placement.

Use of two test methods to ensure accurate surface firmness and stability measurements for accessibility.

PURPOSE: The firmness and stability of indoor and outdoor surfacing are critical to the accessibility and safety of all environments for people with mobility impairments and/or who use mobility devices. ASTM F1951 laboratory test procedures include pass/fail criteria for determining playground surface accessibility by comparing the work to propel up a 1:14 (7.1%) grade ramp to that of the test surface in a wheelchair. A portable instrumented surface indenter (ISI) was developed to validate that accessibility results obtained in the laboratory are maintained in the field where the surface is installed and used. METHODS: Accessibility measurements have been made on indoor and outdoor surfaces tested in the laboratory using both the ASTM F1951 and the ISI over 13 years. Correlations between these two methods were calculated. RESULTS: A strong correlation has been demonstrated for the sum of the ISI firmness and stability results compared to the sum of the ASTM F1951 straight propulsion and turning results (R2=0.9006). CONCLUSIONS: The portable ISI can be used to verify that the firmness and stability of an installed surface in the field correlates to the accessibility results of the surface tested in the laboratory concurrently according to ASTM F1951 and the ISI. Implications for Rehabilitation The Instrumented Surface Indenter (ISI) allows for surfaces in all environments to be tested for firmness and stability, which is critical for wheelchair user safety, especially during rehabilitation when learning to use a wheelchair. The ISI allows for surfaces in all environments to be tested for firmness and stability, which increases access to all indoor and outdoor surfaces, thereby improving the quality of life for people who have mobility impairments and/or use mobility devices, such as canes, crutches, walkers, and wheelchairs. Using the ISI to test the firmness and stability of installed playground surfaces increases access to playgrounds for children with mobility impairments, facilitating developmentally critical peer-play opportunities for children who use mobility devices. Using the ISI to test the firmness and stability of installed playground surfaces increases access to playgrounds for people with mobility impairments, allowing adults who use a mobility device to supervise and play with children in their lives.

Consequences of a cross slope on wheelchair handrim biomechanics.

OBJECTIVE: To test the hypothesis that pushing on a cross slope leads to increased handrim loading compared with that found on a level surface. DESIGN: Case series. SETTING: Biomechanics laboratory. PARTICIPANTS: Twenty-six manual wheelchair users. INTERVENTION: Subjects pushed their own wheelchairs on a research treadmill set to level, 3 degrees , and 6 degrees cross slopes. Propulsion speed was self-selected for each cross-slope condition. Handrim biomechanics were measured for the downhill wheel, using an instrumented wheelchair wheel and a motion capture system. MAIN OUTCOME MEASURES: Speed, peak kinetics (force, rate of loading, torque), push angle, cadence, push distance, and power output were averaged over a 20-push set for each subject and each cross-slope condition. Outcomes were compared across cross slopes using a repeated-measures analysis of variance. RESULTS: Push angle and cadence were unaffected by cross slope. A trend of decreasing self-selected speeds with increasing cross slope was not significant. There were considerable increases in the peak kinetic measures, with the axial moment increasing by a factor of 1.8 on the 6 degrees cross slope (P=.000). More pushes were required to cover the same distance when on a cross slope (P<.034). The power required for propulsion increased by a factor of 2.3 on the 6 degrees cross slope (P=.000). CONCLUSIONS: Users must push harder when on a cross slope. This increased loading is borne by the users' arms, which are at risk for overuse injuries. Exposure to biomechanic loading can be reduced by avoiding cross slopes when possible.

Stroke pattern and handrim biomechanics for level and uphill wheelchair propulsion at self-selected speeds.

OBJECTIVES: To investigate the natural stroke patterns of wheelchair users pushing on a level surface, to determine if users adapt their stroke patterns for pushing uphill, and to assess whether there are biomechanic advantages to one or more of the stroke patterns. DESIGN: Case series. SETTING: Biomechanics laboratory. PARTICIPANTS: Twenty-six manual wheelchair users with a spinal cord injury. INTERVENTION: Subjects pushed their own wheelchairs at self-selected speeds on a research treadmill set to level, 3 degrees , and 6 degrees grades. Stroke patterns were measured using a motion capture system. Handrim biomechanics were measured using an instrumented wheel. MAIN OUTCOME MEASURES: Stroke patterns were classified for both level and uphill propulsion according to 1 of 4 common classifications: arcing, semi-circular, single-looping (SLOP), and double-looping (DLOP). Biomechanic outcomes of speed, peak handrim force, cadence, and push angle were all compared across stroke classifications using an analysis of variance. RESULTS: Only 3 of the 4 stroke patterns were observed. None of the subjects used the semi-circular pattern. For level propulsion, the stroke patterns were fairly balanced between arcing (42%), SLOP (31%), and DLOP (27%). Subjects tended to change their stroke pattern for pushing uphill, with 73% of the subjects choosing the arcing pattern by the 6 degrees grade. No statistically significant differences were found in handrim biomechanics or subject characteristics across stroke pattern groups. CONCLUSIONS: Wheelchair users likely adapt their stroke pattern to accommodate their propulsion environment. Based on the large percentage of subjects who adopted the arcing pattern for pushing uphill, there may be benefits to the arcing pattern for pushing uphill. In light of this and other recent work, it is recommended that clinicians not instruct users to utilize a single stroke pattern in their everyday propulsion environments.

Reduced finger and wrist flexor activity during propulsion with a new flexible handrim.

OBJECTIVE: To test the hypothesis that finger and wrist flexor activity is lower when pushing with a high-friction flexible handrim than with a standard uncoated handrim. DESIGN: Case series. SETTING: Biomechanics laboratory. PARTICIPANTS: Twenty-four manual wheelchair users. INTERVENTION: Subjects pushed their own wheelchairs on a research treadmill set to level, 3 degrees , and 6 degrees grades using both a standard uncoated handrim and a high friction flexible handrim. Propulsion speed was self-selected and held constant between handrim trials. Handrim order was randomized. Finger and wrist flexor muscle activity was measured at the forearm using surface electromyography. MAIN OUTCOME MEASURES: Electromyographic data were rectified and normalized by each subject's maximum voluntary contraction. Total muscle exertion was determined by integrating the rectified signal over each push. Peak and total muscle exertion for each push were averaged across grade conditions and compared across handrims using a repeated measures t test. RESULTS: The flexible handrim resulted in statistically significant reductions in both peak and total forearm muscle activation. Averaging across all subjects and grade conditions, peak muscle activation was reduced by 11.8% (P=.026) and overall muscle exertion was reduced by 14.5% (P=.016). CONCLUSIONS: The flexible handrim was shown to require less finger and wrist flexor activity than a standard uncoated handrim for the same propulsion conditions.

Low-impact wheelchair propulsion: achievable and acceptable.

Incidence of upper-limb overuse injuries among the manual wheelchair population has been found to be associated with hand-rim loading characteristics such as impact and peak loading on the hand rim during propulsion. One proposed method to reduce impact and peak loading is the use of a compliant hand rim, one that can displace relative to the wheel when impacted by the hand. A Variable Compliance Hand-Rim Prototype (VCHP) was designed and used to experimentally optimize the level of compliance through subjective and qualitative propulsion outcome measures. Seventeen manual wheelchair users participated in the study. Subjects propelled their wheelchairs using the VCHP set to each of three compliance levels through a maneuverability test course, as well as on a range of grade conditions using a wheelchair treadmill. Biomechanical measures such as peak hand-rim force, rate of loading at impact, and metabolic demand were assessed during treadmill propulsion bouts. No adverse biomechanical side effects to compliance were found. As compliance was increased, user acceptance decreased. All the subjects found the lowest level of compliance (C1) to be acceptable. Use of the C1 hand rim significantly reduced the peak rate of rise in the hand-rim force on the 6% and 8% grades and significantly reduced the average rate of loading for the 2%, 4%, and 6% grades. This study showed that low-impact wheelchair propulsion is both achievable and acceptable to users.