Performance of wheelchair sports is influenced by the wheelchair-athlete interaction. For example, isometric force generation to the rim and weight distribution between front and rear wheels can
influence performance in wheelchair court sports. Position and movement of the trunk while driving the wheelchair will influence this weight distribution and therefore the rolling resistance of the
wheels. To get more insight into the wheelchair-athlete interaction during wheelchair activities, measurement of these factors is necessary by athletes in their own sports-wheelchair. The aim of this
study is to develop a measurement platform for measuring weight distribution during trunk motion and during measurements of static isometric forces.
Based on literature and interviews with experts, needs and requirements were determined. The platform should; 1) measure the weight distribution between front and rear wheels during trunk motion in
the sagittal plane and 2) measure the maximal isometric forces to the rim in their own wheelchair. Furthermore, the platform must remain in place, the wheelchair must be stable on the platform and the
transport must be easy.
Based on these requirements, the platform is designed and manufactured. To test the reliability of the weight on the balance scales, there were two tests performed; a static and dynamic test. During
the static test, known weights were used to check the platform outcome of weight distribution. During the dynamic test, five participants performed an isometric force test. All participants performed
the dynamic test five times. ICC values were calculated with SPSS (version 22.0) to indicate the reliability.
The measurement platform consisted of two separates plates both with an independent balance scale (underneath connected to a computer). Behind the platform there is a force transducer connected to the
footplate of the wheelchair (MacMesin AFG 1000N). The top of the plates is covered with synthesis basketball court material to improve the ecological validity.
The outcome of the static test, was an ICC of 0.998. The ICC of the dynamic test was 0.955, which is considered as good for these type of measurements 1. Both ICC outcomes re linked to the
reliability of the balance scales.
From the results it can be concluded that the platform can measure reliably weight distribution and can be used in measurements of trunk motion and isometric forces of wheelchair athletes. Trunk
flexion might influence the center of gravity of the athlete and therefore, the weight distribution. In future research the platform will be used to measure the influence of trunk flexion on weight
distribution between the front and rear wheels during wheelchair actions and during maximal isometric force measurements.