A study on effects of backrest thickness on the upper arm and trunk muscle load during wheelchair propulsion

Abstract

[Purpose] The purpose of this study was to investigate the effects of the thickness of a wheelchair backrest provided for support and comfort on upper arm and trunk muscle load during wheelchair propulsion by using accelerometers. [Subjects and Methods] The Fourteen healthy participants were enrolled in this study. The study compared effects of three backrest conditions including no pad, a 3-cm-thick lumbar pad, and a 6-cm-thick lumbar pad. The instruments used for measurement were used two accelerometers. The participants were asked to propel their wheelchairs, which had been equipped with two accelerometers, 30 times. [Results] The intensity of muscle movement with the 3-cm-thick lumbar pad was significantly lower than the intensities with no lumbar pad and the 6-cm-thick lumbar pad. The muscle intensity did not differ significantly between the no pad and 6-cm-thick lumbar pad conditions. [Conclusion] An appropriately thick backrest has good effects on upper arm and trunk muscles during wheelchair propulsion. In the future, we must consider the appropriate backrest thickness for providing wheelchair users with a comfortable wheelchair.

How Was Studied the Effect of Manual Wheelchair Configuration on Propulsion Biomechanics: A Systematic Review on Methodologies

“…Methods: Six articles used overground propulsion and involved experienced MWC users ( 37 , 47 ), novice AB participants ( 19 , 32 , 43 ) or older people with no information on their MWC experience ( 60 ). One article focused on MWC rugby athletes ( 37 ).…”

“…One article focused on MWC rugby athletes ( 37 ). Participants were asked to propel at a comfortable self-selected speed either for at least 4 cycles on a linear path on 4 different surfaces ( 60 ), for 10 m ( 32 ), for 20 m ( 47 ) or for 30 cycles ( 43 ); to perform a combination of 5 m sprints, Illinois agility test and a specific “skill” test ( 37 ), or a combination of a 15 m straight line sprint and a slalom course ( 19 ).…”

“…The six studies used a single MWC for all their participants. The initial configuration was either described through MWC brand, rear-wheel diameter, tire type, handrim diameter, front wheel type, seat width and depth and camber angle ( 47 ); through brand, mass, seat width, depth, height and inclination, cushion thickness and type, side guards material, rear and caster wheel types and diameters, handrim material and camber ( 60 ); through brand and seat height ( 32 ); through fore-aft seat position ( 19 ); through seat height, angle, and tire pressure ( 37 ) or not described ( 43 ). All articles except one ( 43 ) used an adjustable MWC, but only three reported a MWC adaptation to each participant ( 37 , 47 , 60 ), and Kotajarvi et al ( 47 ) specified this adaptation to be the reproduction of the participant's backrest and footrest heights.…”

“…Materials: Regarding measurement devices, the experiments used optoelectronic motion capture systems ( 32 , 47 ), video cameras ( 37 ), instrumented wheels ( 47 , 60 ), IMUs or accelerometers ( 37 , 43 ), and EMG electrodes ( 19 , 32 ).…”