Objective: This study aimed to investigate which characteristics of athlete, wheelchair and athlete-wheelchair interface are the best predictors of wheelchair basketball mobility performance. Design: A total of 60 experienced wheelchair basketball players performed a wheelchair mobility performance test to assess their mobility performance. To determine which variables were the best predictors of mobility performance, forward stepwise linear regression analyses were performed on a set of 33 characteristics, including 10 athlete, 19 wheelchair, and 4 athlete-wheelchair interface characteristics. Results: A total of 8 of the characteristics turned out to be significant predictors of wheelchair basketball mobility performance. Classification, experience, maximal isometric force, wheel axis height, and hand rim diameter—which both are interchangeable with each other and wheel diameter—camber angle, and the vertical distance between shoulder and rear wheel axis—which was interchangeable with seat height—were positively associated with mobility performance. The vertical distance between the front seat and the footrest was negatively associated with mobility performance. Conclusion: With this insight, coaches and biomechanical specialists are provided with statistical findings to determine which characteristics they could focus on best to improve mobility performance. Six out of 8 predictors are modifiable and can be optimized to improve mobility performance. These adjustments could be carried out both in training (maximal isometric force) and in wheelchair configurations (eg, camber angle). https://doi.org/10.1123/jsr.2017-0142 LinkedIn: https://www.linkedin.com/in/annemarie-de-witte-9582b154/ https://www.linkedin.com/in/moniqueberger/ https://www.linkedin.com/in/rienkvdslikke/
MULTIFILE
Daily wheelchair ambulation is seen as a risk factor for shoulder problems, which are prevalent in manual wheelchair users. To examine the long-term effect of shoulder load from daily wheelchair ambulation on shoulder problems, quantification is required in real-life settings. In this study, we describe and validate a comprehensive and unobtrusive methodology to derive clinically relevant wheelchair mobility metrics (WCMMs) from inertial measurement systems (IMUs) placed on the wheelchair frame and wheel in real-life settings. The set of WCMMs includes distance covered by the wheelchair, linear velocity of the wheelchair, number and duration of pushes, number and magnitude of turns and inclination of the wheelchair when on a slope. Data are collected from ten able-bodied participants, trained in wheelchair-related activities, who followed a 40 min course over the campus. The IMU-derived WCMMs are validated against accepted reference methods such as Smartwheel and video analysis. Intraclass correlation (ICC) is applied to test the reliability of the IMU method. IMU-derived push duration appeared to be less comparable with Smartwheel estimates, as it measures the effect of all energy applied to the wheelchair (including thorax and upper extremity movements), whereas the Smartwheel only measures forces and torques applied by the hand at the rim. All other WCMMs can be reliably estimated from real-life IMU data, with small errors and high ICCs, which opens the way to further examine real-life behavior in wheelchair ambulation with respect to shoulder loading. Moreover, WCMMs can be applied to other applications, including health tracking for individual interest or in therapy settings.
DOCUMENT
In wheelchair sports, the use of Inertial Measurement Units (IMUs) has proven to be one of the most accessible ways for ambulatory measurement of wheelchair kinematics. A three-IMU configuration, with one IMU attached to the wheelchair frame and two IMUs on each wheel axle, has previously shown accurate results and is considered optimal for accuracy. Configurations with fewer sensors reduce costs and could enhance usability, but may be less accurate. The aim of this study was to quantify the decline in accuracy for measuring wheelchair kinematics with a stepwise sensor reduction. Ten differently skilled participants performed a series of wheelchair sport specific tests while their performance was simultaneously measured with IMUs and an optical motion capture system which served as reference. Subsequently, both a one-IMU and a two-IMU configuration were validated and the accuracy of the two approaches was compared for linear and angular wheelchair velocity. Results revealed that the one-IMU approach show a mean absolute error (MAE) of 0.10 m/s for absolute linear velocity and a MAE of 8.1◦/s for wheelchair angular velocity when compared with the reference system. The twoIMU approach showed similar differences for absolute linear wheelchair velocity (MAE 0.10 m/s), and smaller differences for angular velocity (MAE 3.0◦/s). Overall, a lower number of IMUs used in the configuration resulted in a lower accuracy of wheelchair kinematics. Based on the results of this study, choices regarding the number of IMUs can be made depending on the aim, required accuracy and resources available.
DOCUMENT
In Europe nearly 10% of the population suffers from diabetes and almost 1% from Rheumatoid Arthritis which can lead to serious problems with mobility and active participation, especially in the ageing population. Pedorthists deliver personalised designed and manufactured orthopaedic footwear or insoles for these patients. However, despite their often laborious efforts upfront, the industry has very little means to quantify how successful the fitting and function of a shoe is. They have to rely on subjective, qualitative measures such as client satisfaction and diminishing of complaints. Although valuable, the need for objective quantitative data in this field is growing. Foot plantar pressure and shear forces are considered major indicators of potential foot problems. Devices to measure plantar pressure slowly gain terrain as providers of objective quantitative data to guide orthotic design and manufacturing. For shear forces however, measuring devices are not yet commercial available. Although shear forces are considered as a major contributor to ulcer formation in diabetic feet, their exact role still requires elucidation and quantification. This project aims to develop a prototype of an in-shoe wearable device that measures both shear forces and pressure using state-of-the-art developments in sensor technologies, smart textiles and wireless data transfer. The collaboration of pedorthists’ small and medium-sized enterprises (SME)’s with medical device engineering companies, knowledge institutes,technical universities and universities of applied sciences in this project will bring together the different fields of expertise required to create an innovative device. It is expected that the tool will be beneficial to improve the quality of pedorthists’ services and potentially reduce health insurance costs. Furthermore, it can be used in new shear forces research and open new business potential. However, the eventual aim is to improve patient care and help maintain personal mobility and participation in society.
