Relationship between questionnaire survey results of vibration complaints of wheelchair users and vibration transmissibility of manual wheelchair

Abstract

Objective: Clarify the relation between the complaints of wheelchair users and the vibration characteristics of the wheelchair, to improve wheelchair comfort and design.Methods: The questionnaires were distributed to 33 wheelchair users directly by the experimenter in order to identify the causes of complaints from wheelchair vibrations that they experienced. The vibration transmissibility of wheelchairs of ten subjects was measured to clarify the causes of complaints of wheelchair vibration according to the ISO 10326-1 standard in the laboratory using a broadband random vibration spectrum with a frequency-weighted vibration magnitude of 0.1 ms 2 r.m.s. over the frequency range from 0.2 to 100 Hz. Each vibration exposure lasted 60 seconds.Results: The following findings were clear from the questionnaire results; (i) the vibration from the wheelchair affected psychological comfort; (ii) the effects of different riding surfaces were important engineering issues affecting wheelchair ride comfort; (iii) the wheelchair users felt the vibration during wheelchair usage at locations on the neck, lower back and buttocks; (iv) vertical vibration was the most noticeable vibration from the wheelchair to each participant's body. The following findings were clear from the results of the transmissibility measurement of the wheelchair; (i) the resonance frequency-ranges of the transmissibility of the wheelchair showed significant differences between the subjects; (ii) intra-subject variability from three repeated transmissibility measurements was small; (iii) the first resonant frequency occurred approximately 5 to 7 Hz and the second resonant frequency occurred at around 8 Hz and the third resonant frequency occurred approximately 13 to 15 Hz; (iv) the magnitude of the peak transmissibility varied from 1.3 to 2.6.Conclusion: From the comparison of the results of questionnaires and the transmissibility measurement of the wheelchair, the resonance frequency-ranges of the maximum vibration transmissibility of the manual wheelchairs were consistent with the frequency-ranges of the body parts of the causes of the complaints of wheelchair users. In addition, from these experimental results, it was suggested that the main point for improving a wheelchair user's comfort was to reduce the wheelchair seat vibration transmissibility at around 8 Hz and also to design wheelchair stiffness and damping characteristics to minimize vibration transmission at specific frequencies at body locations that caused the discomfort reported by wheelchair users.

Effect of Rear Wheel Suspension on Tilt‐in‐Space Wheelchair Shock and Vibration Attenuation

“…However, tilt‐in‐space wheelchair users spend large periods of time in their chair, so even small reductions in shock and vibration most likely have positive health benefits. As previously identified, besides improving comfort, potential health benefits include, but are not limited to, reductions in low back pain, neck pain, muscle fatigue, early degeneration of the lumbar spine, herniated lumbar discs, and spinal discomfort and pain [3‐11]. Future research should explore the mechanisms of injury caused by shock and vibration exposure in the wheelchair population, and determine a reduction necessary for health benefits and a standard protocol for evaluating wheelchair exposure.…”

“…Some secondary health conditions may be induced by repeated shock and vibration exposure. Instantaneous peak acceleration, or shock, and whole‐body vibration exposure has been correlated to low back pain, neck pain, muscle fatigue, early degeneration of the lumbar spine, herniated lumbar discs, and spinal discomfort and pain [3‐11]. The International Organization for Standardization (ISO) established methods to quantify shock and whole‐body vibration exposure and the risks associated with exposure in ISO 2631‐1 [12].…”

Head support in wheelchairs (scoping review): state-of-the-art and beyond

“…Wheelchair users can also be exposed to harmful whole-body vibrations due to irregularities in the road and obstacles during wheelchair usage in outdoor conditions. Research has focussed on quantifying the wheelchair vibration characteristics in the laboratory [72] and in (simulated) outdoor conditions, driving over different road conditions [73] and typically experienced obstacles [74]. Some evidence is available for the influence of driving on head balance.…”

Survey on the influencing factors of human comfort in a long-period frequent blast vibration environment

“…And found that using surveys to establish baseline communication levels with neighbors could advance public relations for mining operations by providing insight and direction for site specific public relations programs. Maeda, et al [35] conducted the questionnaires distributed to 33 wheelchair users directly by the experimenter in order to identify the causes of complaints from wheelchair vibrations that they experienced. Khan and Sundström [36] studied three hundred thirty Swedish passengers using a questionnaire survey on vibration comfort in Swedish Inter-City Trains.…”