The Impact of the Human Body Position Changes During Wheelchair Propelling on Motion Resistance Force: A Preliminary Study

Mapping wheelchair functions and their associated functional elements for stair climbing accessibility: a systematic review

PURPOSE

Wheelchair (WC) design elements are subjected to the accessibility and assistive needs of a person with locomotor disability. In order to pursue a holistic design for a stairclimbing WC, there is a need for literature review on WC functions reported for both stair climbing and plane surface movement.

METHODS

A total of 112 Research articles are reviewed for the purpose of extracting the relationship between WC design elements and the functions associated with them. Stairclimbing technologies are reviewed for their technological assessment in terms of functional elements associated with stairclimbing. Cross-functional mapping between functional elements and their dominant function is performed. Heat map for primary user needs and associated design elements is generated from cross mapping.

CONCLUSIONS

A design gap for user's functional needs is indicated from the review of literature on prototypes and products of WC. The literature in stairclimbing technology is primarily focussed on stair climbing capability and not on the other functional needs, such as safety, ride comfort, seat comfort, manoeuvrability, etc.Implications for rehabilitationFor attaining the goal of an effective rehabilitation, it is important to design and develop an assistive technology that can provide maximum accessibility and functioning for a person with disability. In case of locomotor disability, wheelchair (WC) is the most empowering tool that can assist people in both accessibility and activities of daily living. This review of literature was conducted to draw out the functions fulfilled by a WC, such as safety, comfort, propulsion for its users and the associated WC elements like seat, wheels, backrest, etc., that are required to fulfil those functions.WC being the most important technological intervention in the life of a person who cannot walk should be designed with the highest level of empathy. Therefore, each and every aspect of the user's physical and emotional needs should be catered up to the limits of engineering design. The research on stair climbing technologies has also grown exponentially, fuelled by technological growth in engineering mechanisms, ambient awareness sensors, actuators, etc. The review attempts to envelop such technologies and consolidate them on the basis of their capabilities and efficacies.The virtue of stair climbing has been realized through some novel and innovative mechanisms reviewed in this article that can be integrated with the research in field of functional elements required to carry out primary functions of a disabled person, such as safety, comfort, intuitiveness, etc. This review can help in coupling both of them in a more rational way where a designer who is designing the technology is more empathetic towards the design for accessibility. It can also help user in becoming more confident towards adapting a new assistive technology.

The Symmetry of the Muscle Tension Signal in the Upper Limbs When Propelling a Wheelchair and Innovative Control Systems for Propulsion System Gear Ratio or Propulsion Torque: A Pilot Study

Innovative wheelchair designs require new means of controlling the drive units or the propulsion transmission systems. The article proposes a signal to control the gear ratio or the amount of additional propulsion torque coming from an electric motor. The innovative control signal in this application is the signal generated by the maximum voluntary contraction (MVC) of the muscles of the upper limbs, transformed by the central processing unit (CPU) into muscle activity (MA) when using a wheelchair. The paper includes research on eight muscles of the upper limbs that are active when propelling a wheelchair. Asymmetry in the value for MVC was found between the left and right limbs, while the belly of the long radial extensor muscle of the wrist was determined to be the muscle with the least asymmetry for the users under study. This pilot research demonstrates that the difference in mean MVCmax values between the left and the right limbs can range from 20% to 49%, depending on the muscle being tested. The finding that some muscle groups demonstrate less difference in MVC values suggests that it is possible to design systems for regulating the gear ratio or additional propelling force based on the MVC signal from the muscle of one limb, as described in the patent application from 2022, no. P.440187.

The Relationship between Clinical Tests, Ultrasound Findings and Selected Field-Based Wheelchair Skills Tests in a Cohort of Quadriplegic Wheelchair Rugby Athletes: A Pilot Study

Manual wheelchair use may determine shoulder joint overload and rotator cuff injury. Chronic shoulder pathologies can also influence the propulsion ability of wheelchair athletes with spinal cord injury (SCI) during sport activities. However, the relationship between shoulder pathology and wheelchair performances has never been explored. Therefore, the study aimed to investigate the correlation between shoulder pathologic findings with clinical tests and ultrasonography evaluation and the results of wheelchair performance tests. Nineteen quadriplegic wheelchair rugby players were evaluated to investigate the association between clinical and ultrasound shoulder pathologic findings and their correlation with the performance of field-based selected wheelchair skills tests (WSTs). The outcome measures were the International Wheelchair Rugby Classification Score, dominant and non-dominant Physical Examination Shoulder Score, and dominant and non-dominant Ultrasound Shoulder Pathology Rating Scale (USPRS). The WST was measured at the beginning and at one-year follow-up. A statistically significant correlation was found between the time since SCI and dominant USPRS (p < 0.005). The non-dominant USPRS was strongly related to WST at the beginning (p < 0.005) and the end of the study (p < 0.05). Data suggest that the severity of the non-dominant shoulder pathology detected on the ultrasound is related to lower performance on the WST. Chronic manual wheelchair use could be responsible for dominant SCI shoulder joint and rotator cuff muscle damage, while non-dominant USPRS could be related to performance on the WST.