GDynamic stiffness and transmissibility of commercially available wheelchair cushions using a laboratory test method

Abstract

Abstract-Evidence suggests that wheelchair (WC) users are exposed to unhealthy levels of vibration during WC use. Health risks associated with vibration exposure include vertebral disc degeneration and back pain, which may consequently decrease the function and independence of WC users. Some evidence suggests that the cushions used in WCs may amplify vibrations, although conclusive evidence has not been presented in the literature. This study evaluated and compared the transmissibility of commercially available WC cushions with two laboratory test methods: (1) direct measurement of transmissibility while human subjects propelled a WC over a road course with different cushions and (2) characterization of cushions with a material testing system (MTS) combined with mathematical models of the apparent mass of the human body. Results showed that although dynamic characterization of WC cushions is possible with an MTS, the results did not correlate well with the transmissibility obtained in the WC road course. Significant differences were found for transmissibility among the cushions tested, with the air-based cushions having lower transmissibility than the foam-or gel-based cushions.

Effect of Wheelchair Frame Material on Users’ Mechanical Work and Transmitted Vibration

“…As wheeling velocity does have an effect on vibration [28], this variation may have altered the reproducibility between trials. Wolf et al [29] controlled time to complete a trial at ±0.5%, while others did not control velocities at all [24, 25, 30]. For future work, we believe that velocity should be controlled during all trials.…”

“…A variant of this norm was also used in DiGiovine et al [24] and Garcia-Mendez et al [25] to measure the vibration transmissibility of seat cushions. They made the ratio between the vibration measured on the subject (output) and the vibration measured below the seat (input).…”

Vibration Transmission during Manual Wheelchair Propulsion: A Systematic Review

“…Frequencies of vibration to which MWC users are exposed were identified with an experimental modal analysis of the MWC (i.e., MWC eigenfrequencies) (3 articles), as the peaks of f-Acc (4 articles), or of T f-Acc (5 articles). T f-Acc were observed between the floor and the seat [30], between the MWC frame and the participant's head [31], through the cushion [54], between the seat and the participant's head [40,42], or the backrest and the participant's head [40,42].…”

Describing the effect of a first aid training program on the first aid knowledge and attitudes of female secondary school students in Jeddah – Saudi Arabia

“…The research was used an adapted questionnaire based on the study conducted by Sahar M. Yakout et al (9) . As the questionnaire was distributed amongst the secondary school female students sample, the questionnaire was used as a part of a pilot study and distributed to a small group of 5 students selected from the chosen school for study so that the required modifications may be done prior to distributing the final questionnaire to the representative population.…”