Accessible Autonomous Transportation and Services: Design Considerations From the Perspective of Consumers and Providers.

OBJECTIVE: To understand the priorities and preferences of people with disabilities (PwDs) and older adults regarding accessible autonomous vehicles (AVs) to address existing transportation barriers. DESIGN: Two national surveys, Voice of the Consumer and Voice of the Provider, were conducted to gather feedback from accessible AV consumers and providers, respectively, in the United States. SETTING: This U.S.-based study focused on PwDs and older adults who may face transportation challenges and those who provide or design AV solutions. PARTICIPANTS: The 922 consumers and 45 providers in the surveys encompassed a diverse range of disability types, caregiver roles, and age groups (N = 967). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The main outcomes were consumer usage needs and provider preferences for features in accessible autonomous transportation. Patterns in usage needs and feature preferences through 2-step clustering algorithm were applied subsequent to the descriptive analysis of participant demographics and their responses. RESULTS: Participants strongly preferred AV features enhancing personal transportation, especially for rural medical appointments. Most sought comprehensive AV automated features. Wheelchair users emphasized accessible entrances, particularly for lower-income brackets ($25,000-$49,000). Provider priorities closely aligned with consumer preferences, reinforcing content validity. CONCLUSIONS: The study highlights the importance of prioritizing wheelchair accessibility in AVs and improving access to medical appointments, especially in rural and low-income communities. Implications include developing inclusive AV services for PwDs and underserved populations. The research establishes a foundation for a more equitable and accessible transportation landscape through AV technology integration.

Understanding Travel Considerations and Barriers for People with Disabilities to Using Current Modes of Transportation Through Journey Mapping.

This study aimed to apply a journey mapping methodology to identify travel considerations and barriers for people with disabilities (PWDs) at each travel stage, from considering a trip through to arriving at the destination for their current modes of transportation, with the objective of understanding and avoiding "pain points" during a transition to autonomous driving systems. Twenty PWDs, including those with physical, visual, aural, cognitive, and combined physical/visual impairments, participated in a semistructured one-on-one interview. Descriptive statistics were used for demographic information, and qualitative content analysis was used to analyze the transcribed interviews and extract themes. Themes were further organized by the modes of transportation used. The top four themes in considering and planning a trip were third-party assistance availability (private vehicle, public transportation, and paratransit), finding an accessible or suitable parking space (private vehicle), access to a service location (public transportation and paratransit), and transportation schedules (public transportation and paratransit). The top four travel barriers to locating, entering, riding, and exiting transportation and arriving at the destination were vehicle ingress/egress (private vehicle and public transportation), concerns about wheelchair securement (public transportation and paratransit), requiring third-party assistance (private vehicle and public transportation), and accessibility to service locations (public transportation). The study suggests that to mitigate travel considerations and barriers for PWDs, vehicle-specific barriers and infrastructure issues should be addressed simultaneously. We anticipate that the findings will provide insights into the design and development of autonomous vehicles, to better accommodate the needs of PWDs.

Reliability of 3D Depth Motion Sensors for Capturing Upper Body Motions and Assessing the Quality of Wheelchair Transfers.

Wheelchair users must use proper technique when performing sitting-pivot-transfers (SPTs) to prevent upper extremity pain and discomfort. Current methods to analyze the quality of SPTs include the TransKinect, a combination of machine learning (ML) models, and the Transfer Assessment Instrument (TAI), to automatically score the quality of a transfer using Microsoft Kinect V2. With the discontinuation of the V2, there is a necessity to determine the compatibility of other commercial sensors. The Intel RealSense D435 and the Microsoft Kinect Azure were compared against the V2 for inter- and intra-sensor reliability. A secondary analysis with the Azure was also performed to analyze its performance with the existing ML models used to predict transfer quality. The intra- and inter-sensor reliability was higher for the Azure and V2 (n = 7; ICC = 0.63 to 0.92) than the RealSense and V2 (n = 30; ICC = 0.13 to 0.7) for four key features. Additionally, the V2 and the Azure both showed high agreement with each other on the ML outcomes but not against a ground truth. Therefore, the ML models may need to be retrained ideally with the Azure, as it was found to be a more reliable and robust sensor for tracking wheelchair transfers in comparison to the V2.

Feasibility, acceptability, and preliminary efficacy of a handcycling high-intensity interval training program for individuals with spinal cord injury.

STUDY DESIGN: Pilot nonrandomized clinical trial. OBJECTIVES: To examine the feasibility, acceptability, and preliminary efficacy of performing handcycling high-intensity interval training (HIIT) for 6 weeks in wheelchair users with spinal cord injury. SETTING: Participant's home. METHODS: Participants completed pre- and postgraded exercise stress tests, exercise surveys and 6 weeks of handcycling HIIT. The HIIT program consisted of two weekly, 25 min supervised at-home sessions (2-3 min warm-up, then ten intervals of cycling with a ratio of 1 min work at 90% peak power output (PPO) to 1 min recovery at 0-20% PPO, then 2-3 min cool down). Real-time power output and heart rate were recorded via sensors and a bike computer. The sensor data were analyzed to evaluate training efficacy. RESULTS: Seven of the ten enrolled participants (70%) completed the study. All but one completed the required 12 sessions. The participants met at least 1 of the HIIT target intensity criteria in 76 out of 89 total sessions (85.4%) performed. Participants expressed a high level of enjoyment on the Physical Activity Enjoyment Scale, mean (SD) = 114.8 (11.3), and satisfaction with the overall experience. Five of the seven participants (71%) who completed the study felt an increase in endurance, function, and health. Objective physiological changes showed mixed results. CONCLUSIONS: Six weeks of handcycling HIIT appears to be safe, feasible and acceptable. A longer HIIT work interval may be needed to elicit significant physiological responses. Future investigation of the feasibility and efficacy of differing HIIT parameters is needed.

Immediate Biomechanical Implications of Transfer Component Skills Training on Independent Wheelchair Transfers.

OBJECTIVE: To evaluate the immediate effects of transfer training based on the Transfer Assessment Instrument (TAI) on the upper limb biomechanics during transfers. DESIGN: Pre-post intervention. SETTING: Biomechanics laboratory. PARTICIPANTS: Full-time manual wheelchair users (N=24) performed 5 transfers to a level height bench, while their natural transfer skills were scored using the TAI, and their biomechanical data were recorded. INTERVENTION: Participants with 2 or more component skill deficits were invited to return to receive personalized transfer training. MAIN OUTCOME MEASURES: TAI part 1 summary scores and biomechanical variables calculated at the shoulder, elbow, and wrist joints were compared before and immediately after transfer training. RESULTS: Sixteen of the 24 manual wheelchair users met the criteria for training, and 11 manual wheelchair users came back for the revisit. Their TAI part 1 summary scores improved from 6.31±.98 to 9.92±.25. They had significantly smaller elbow range of motion, shoulder resultant moment, and rates of rise of elbow and wrist resultant forces on their trailing side during transfers after training (P<.05). On the leading side, shoulder maximum internal rotation and elevation angles, and shoulder resultant moments and rates of rise of shoulder resultant force and moment decreased after training (P<.04). CONCLUSIONS: The TAI-based training showed short-term beneficial biomechanical effects on wheelchair users' upper limbs, such as better shoulder positioning and lower joint loadings. If the skills are practiced longer-term, they may help protect the upper limbs from developing pain and injuries.

Upper limb joint kinetics of three sitting pivot wheelchair transfer techniques in individuals with spinal cord injury.

STUDY DESIGN: Repeated measures design. OBJECTIVE: This study compared the upper extremity (UE) joint kinetics between three transfer techniques. SETTING: Research laboratory. METHODS: Twenty individuals with spinal cord injury performed three transfer techniques from their wheelchair to a level tub bench. Two of the techniques involved a head-hips method with leading hand position close (HH-I) and far (HH-A) from the body, and the third technique with the trunk upright (TU) and hand far from body. Motion analysis equipment recorded upper body movements and force sensors recorded their hand and feet reaction forces during the transfers. RESULTS: Several significant differences were found between HH-A and HH-I and TU and HH-I transfers indicating that hand placement was a key factor influencing the UE joint kinetics. Peak resultant hand, elbow, and shoulder joint forces were significantly higher for the HH-A and TU techniques at the trailing arm (P < 0.036) and lower at the leading arm (P < 0.021), compared to the HH-I technique. CONCLUSION: Always trailing with the same arm if using HH-A or TU could predispose that arm to overuse related pain and injuries. Technique training should focus on initial hand placement close to the body followed by the amount of trunk flexion needed to facilitate movement.

Effect of a Wheelie Training Method With the Front Wheels on a Ramp in Novice Able-Bodied Participants: A Randomized Controlled Trial.

The objective of this study was to determine if wheelie training that begins with learning how to balance with the front wheels on a ramp would increase the success rate, reduce the training time, and improve retention rates. A randomized controlled trial design was used to evaluate the effectiveness of wheelie training on a ramp setting (ramp group, n = 26) and conventional training (conventional group, n = 26). The main outcome measures were success rates in achieving wheelie competence, training time, and the retention rate in 7 and 30 days respectively. The results showed that the success rate for each training group both reached 100%. The mean training times for the conventional group and the ramp group were 86.0 ± 35.7 and 76.0 ± 25.8 minutes. Training time was not significantly affected by the training method (p = 0.23), but it was affected by gender, with women requiring an average of 92.0 ± 31.4 minutes in comparison with 70.0 ± 27.5 minutes for men (p = 0.01). The skill retention rate after 7 and 30 days was 100% for both groups. Neither success rate nor training time for wheelie skill acquisition by learners were improved by learning wheelie balance on a ramp. However, a high retention rate of wheelie skills for both training groups was found, which implies that success can be achieved by training on a ramp used in this study.

TransKinect: a computer vision and machine learning clinical decision support system for automatic independent wheelchair transfer technique assessment.

BACKGROUND: Physical and occupational therapists provide routine care for manual wheelchair users and are responsible for training and assessing the quality of transfers. These transfers can produce large loads on the upper extremity joints if improper sitting-pivot-technique is used. Methods to assess quality of transfers include the Transfer Assessment Instrument, a clinically validated tool derived from quantitative biomechanical features; however, adoption of this tool is low due to the complex usage requirements and speed of typical transfers. OBJECTIVE: The objective of this study is to develop and validate a computer vison and machine learning solution to better implement the Transfer Assessment Instrument in clinical settings. METHODS: The prototype system, TransKinect, consists of an infrared depth sensor and a custom software application; usability testing was carried out with fifteen therapists who performed two transfer assessments with the TransKinect. Proficiency in using features, usability, acceptability and satisfaction were analysed with validated surveys and themes were extracted from the qualitative feedback. RESULTS: The therapists were able to successfully complete the transfer quality assessments with 86.7 ± 5.4% proficiency. Total scores for System Usability Scale (77.6 ± 14.7%) and Questionnaire for User Interface Satisfaction (83.5 ± 8.7%) indicated that the system was usable and satisfactory. Qualitative feedback indicated that TransKinect was user-friendly, easy to learn, and had high potential. DISCUSSION: The results support TransKinect as a potential clinical decision support system for therapists for the comprehensive assessment of independent transfer technique. Future research is needed to investigate the utility and acceptance of TransKinect in real clinical environments. Implications for RehabilitationMachine learning and computer vision can be used to analyze transfer techniqueTransKinect is a usable and user-friendly means for therapists to automate analysisSummary reports and videos of transfers show high potential for clinical useAdoption of TransKinect can increase quality of care for manual wheelchair users.

Development and content validity of the caregiver assisted transfer technique instrument.

Informal caregivers often provide transfer assistance to individuals with disabilities; however, repeated transfers are associated with a high risk of musculoskeletal pain and injury, and training and education around transfers is minimal. The purpose of this study was to develop and assess the content validity of a new tool, the Caregiver Assisted Transfer Technique Instrument (CATT), which could be used to provide an objective indicator of transfer performance. Item importance, clarity, and appropriateness of responses were rated on a five-point Likert scale by clinicians (n = 15), informal caregivers (n = 10), and individuals with spinal cord injury (n = 5). The content validity index and modified Kappa of each item was calculated. Participants also provided qualitative feedback on item content. In general, items were rated favorably for their importance (4.47 to 5.00), clarity (4.33 to 4.90), and appropriateness of responses (4.38 to 4.90), and most items had excellent content validity (k* ≥ 0.75). Feedback from participants led to the creation of two versions of the CATT: one for manual lifting techniques (CATT-M) and one for transfers performed via lift-based technologies (CATT-L). Future work will focus on establishing the reliability and validity of the CATT as well as developing training and education interventions surrounding assisted transfers.

Discovering Provider Awareness of Mobility Assistive Technologies and Clinical Guidelines- A Comparative Analysis with Consumer Responses.

OBJECTIVE: This study aims to enhance the accessibility and quality of mobility assistive technology (MAT) by investigating and bridging knowledge gaps between MAT providers and consumers with ambulatory limitations. DESIGN: A survey was conducted among MAT providers in the United States, consisting of sections on awareness, knowledge importance and desire, and knowledge sources. The responses were compared to data collected from consumers in a previous study. RESULTS: A total of 144 MAT providers participated, with 60% having received academic or professional training in relevant fields. Analysis revealed significant knowledge gaps between providers and consumers, particularly in AT assessment tools and knowledge sources. Moderate gaps were also observed in areas such as clinical practice guidelines, desired MAT information, and knowledge sources. However, the gaps in other areas were relatively small. CONCLUSION: This study highlights the knowledge gaps between MAT providers and consumers, hindering the optimal utilization and fulfillment of user needs. Providers possess valuable information that consumers may lack, positioning them as primary knowledge sources. Addressing these gaps through targeted interventions, improved communication channels, and enhanced education can enhance the utilization of MAT and improve outcomes for individuals with ambulatory limitations.

Basic psychometric properties of the transfer assessment instrument (version 3.0).

OBJECTIVES: To refine the Transfer Assessment Instrument (TAI 2.0), develop a training program for the TAI, and analyze the basic psychometric properties of the TAI 3.0, including reliability, standard error of measurement (SEM), minimal detectable change (MDC), and construct validity. DESIGN: Repeated measures. SETTING: A winter sports clinic for disabled veterans. PARTICIPANTS: Wheelchair users (N=41) who perform sitting-pivot or standing-pivot transfers. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: TAI version 3.0, intraclass correlation coefficients, SEMs, and MDCs for reliable measurement of raters' responses. Spearman correlation coefficient, 1-way analysis of variance, and independent t tests to evaluate construct validity. RESULTS: TAI 3.0 had acceptable to high levels of reliability (range, .74-.88). The SEMs for part 1, part 2, and final scores ranged from .45 to .75. The MDC was 1.5 points on the 10-point scale for the final score. There were weak correlations (ρ range, -.13 to .25; P>.11) between TAI final scores and subjects' characteristics (eg, sex, body mass index, age, type of disability, length of wheelchair use, grip and elbow strength, sitting balance). CONCLUSIONS: With comprehensive training, the refined TAI 3.0 yields high reliability among raters of different clinical backgrounds and experience. TAI 3.0 was unbiased toward certain physical characteristics that may influence transfer. TAI fills a void in the field by providing a quantitative measurement of transfers and a tool that can be used to detect problems and guide transfer training.

A high prevalence of manual wheelchair rear-wheel misalignment could be leading to increased risk of repetitive strain injuries.

PURPOSE: To determine the prevalence and severity of manual wheelchair rear wheel misalignment in community-dwelling manual wheelchair users and estimate the associated increases in rolling resistance (RR) and risk of repetitive strain injuries (RSIs). MATERIALS AND METHODS: Data were collected in an outpatient rehabilitation clinic, a university research laboratory, and at adaptive sporting events in the United States. Two hundred active, self-propelling manual wheelchair users were recruited. Angular misalignment (referred to as toe angle) while the wheelchair was loaded with the user, and the difference between the maximum and minimum toe angle (referred to as slop) with the wheelchair unloaded. RESULTS: Average results for toe angle and slop (movement in the rear wheels) were 0.92 and 0.61 degrees, respectively. Using a lab-based testing method, we quantified the impact of increased RR forces due to misalignment in increased RR forces. Our results indicate that the average toe angle while under load and slop, without loading, measured in the community increase required propulsion force by 3.0 N. Combined toe angle and slop (i.e., the worst-case scenario) added increased propulsion force by 3.9 N. CONCLUSIONS: We found that rear-wheel misalignment was prevalent and severe enough that it may increase the risk for RSIs and decrease participation. To mitigate this issue, future work should focus on reducing misalignment through improved maintenance interventions and increased manufacturing quality through more stringent standards.Implications for RehabilitationThe work reveals a previously unknown and significant contributor to RR that could have health implications for users who self-propel.Maintenance and repairs should be adjusted to help reduce the impact of misalignment.Our results suggests that WC designers should take additional care to designs wheels and frames to minimize misalignment.Service providers setting up wheelchairs should take additional care to make sure the wheels are aligned.Users should monitor misalignment and prioritize maintaining or having their chair repaired when misalignment occurs.

Preliminary evaluation of an automated robotic transfer assist device in the home setting.

PURPOSE: The purpose of this study was to examine the effects of six weeks of routine use of a novel robotic transfer device, the AgileLife Patient Transfer System, on mobility-related health outcomes, task demand, and satisfaction relative to previous transfer methods. MATERIALS AND METHODS: Six end users and five caregivers used the system in their homes for six weeks. Participants completed several surveys examining perceived demands related to preparing and performing a transfer and mobility-related health outcomes pre and post intervention. Participants were also asked about their satisfaction with using the technology compared to previous transfer methods. RESULTS: Both end users and caregivers reported reduction in perceived physical demand (p = 0.007) and work (p ≤ 0.038) when preparing for and performing a transfer. End users indicated that the device intervention had a positive impact, indicating some improvements to health-related quality of life as well as improved competence, adaptability, and self-esteem post-intervention. All participants were highly likely to recommend the technology to others. CONCLUSION: The AgileLife Patient Transfer System is a promising new form of transfer technology that may improve the mobility and mobility-related health of individuals with disabilities and their caregivers in home settings.Implications for rehabilitationRobotic transfer assistance reduced physical demand and work among end users and caregivers.The robotic device had a positive impact on some quality of life outcomes after 6 weeks of use.Users were highly likely to recommend the robotic transfer device to others.

Comparison of trunk mechanics and spatiotemporal outcomes in caregivers using a robotic assisted transfer device and a mobile floor lift.

OBJECTIVE: The purpose of this study was to compare trunk mechanics, distance covered, and average instantaneous velocity and acceleration recorded with caregivers performing transfer tasks using a research mannequin with both a prototype robotic assisted transfer device (RATD) and a mobile floor lift. DESIGN: Cross-Sectional. SETTING: Biomechanics Lab and Human Engineering Research Laboratories. PARTICIPANTS: Caregivers (N = 21). INTERVENTION: Robotic Assisted Transfer Device. OUTCOME MEASURES: Range of flexion-extension, lateral bend, and axial rotation; distance covered; average instantaneous velocity and acceleration. RESULTS: Caregivers performing transfers using the RATD as compared to when using the moble floor lift reported significantly smaller range of trunk flexion-extension, lateral bending, and axial rotation, and reported lower pelvic based distance covered and slower average instantaneous velocity and acceleration (P < 0.001). CONCLUSION: The design and usability of a RATD indicates design driven mobility advantages over clinical standard mobile floor lifts due to its ability to expand the workspace while further reducing risk factors for low back pain. While the concept is promising, further testing is required to address limitations and confirm the concept for clinical applications.

Accessible autonomous transportation and services: voice of the consumer - understanding end-user priorities.

PURPOSE: This study aimed to explore the requirements for accessible Autonomous Vehicles (AVs) and AV services from a consumer perspective, focusing on people with disabilities (PwDs) and older adults. METHODS: Two national surveys were conducted, capturing current transportation trends and AV priorities. Participants (n = 922) with disabilities and older adults were included in the analysis. RESULTS: Transportation choices exhibited significant divergence based on the underlying causes of disabilities, showcasing distinct inclinations and impediments within each category. AV services, encompassing family conveyance and package delivery, proved integral, but their specific desirability fluctuated in accordance with the nature of disabilities. Notably, medical appointments emerged as the foremost AV utilisation requirement, particularly pronounced among individuals with hearing impairments. Preferences for orchestrating AV rides and the preferred vehicle types displayed disparities linked to the various disability classifications. The employment of mobile applications, websites, and text messages were preferred mediums for arranging rides. Features such as automated route guidance and collision prevention garnered unanimous precedence among AV attributes. Key priorities, spanning wheelchair accessibility, user profiles, and seamless communication with AVs, were universally emphasised across all participant clusters. The study indicated a moderate comfort level with AV deployment, implying the potential for favourable reception within the population of PwDs and older adults. CONCLUSION: The study highlights the significance of considering diverse needs in accessible AV development of vehicle and infrastructure and policies.

The findings inform evidence-based interventions and programmes that prioritise accessibility needs, promoting social inclusion and equitable transportation solutions.Continued research and advocacy are essential for successful autonomous vehicle integration, catering to the needs of all individuals.

Accessible autonomous transportation and services: a focus group study.

PURPOSE: Existing automated vehicle transportation guidelines and regulations have minimal guidance to address the specific needs of people with disabilities. Accessibility should be at the forefront to increase autonomy and independence for people with disabilities. The purpose of this research is to better understand potential facilitators and barriers to using accessible autonomous transportation. METHODS: Focus groups were conducted with key stakeholders derived from people with disabilities (n = 5), travel companions/caregivers (n = 5), and transportation experts or designers (n = 11). RESULTS: The themes include describing stakeholder perceptions across all three groups by identified themes: autonomous vehicle assistive technology, autonomy vs automation, cost, infrastructure, safety & liability, design challenges, and potential impact. CONCLUSION: Specific gaps and needs were identified regarding barriers and facilitators for transportation accessibility and evidence-based guidance. These specific gaps can help to formulate design criteria for the communication between, the interior and exterior of accessible autonomous vehicles.

Accessible and affordable autonomous transportation may increase mobility and the autonomy of people with disabilities to travel spontaneously.Autonomous vehicles and services should be designed to accommodate various types of disabilities such as multimodal and multilingual device communication.Safety and liability regulatory protocols need to be developed for incidents and emergencies.Wheelchair user, especially people who use powered devices, would need systems for ingress/egress, docking, and occupant restraints.

Effect of backrest height on wheelchair propulsion biomechanics for level and uphill conditions.

OBJECTIVE: To evaluate the effect of backrest height on wheelchair propulsion kinematics and kinetics. DESIGN: An intervention study with repeated measures. SETTING: University laboratory. PARTICIPANTS: Convenience sample included manual wheelchair users (N=36; 26 men and 10 women) with spinal cord injuries ranging from T8 to L2. INTERVENTION: Participants propelled on a motor-driven treadmill for 2 conditions (level and slope of 3°) at a constant speed of 0.9 m/s while using in turn a sling backrest fixed at 40.6 cm (16 in) high (high backrest) and a lower height set at 50% trunk length (low backrest). MAIN OUTCOME MEASURES: Cadence, stroke angle, peak shoulder extension angle, shoulder flexion/extension range of motion, and mechanical effective force. RESULTS: Pushing with the low backrest height enabled greater range of shoulder motion (P<.01), increased stroke angle (P<.01), push time (P<.01), and reduced cadence (P=.01) regardless of whether the treadmill was level or sloped. CONCLUSIONS: A lower cadence can be achieved when pushing with a lower backrest, which decreases the risk of developing upper-limb overuse related injuries. However, postural support, comfort, and other activities of daily living must also be considered when selecting a backrest height for active, long-term wheelchair users. The improvements found when using the low backrest were found regardless of slope type. Pushing uphill demanded significantly higher resultant and tangential force, torque, mechanical effective force, and cadence.

Comparison between overground and dynamometer manual wheelchair propulsion.

Laboratory-based simulators afford many advantages for studying physiology and biomechanics; however, they may not perfectly mimic wheelchair propulsion over natural surfaces. The goal of this study was to compare kinetic and temporal parameters between propulsion overground on a tile surface and on a dynamometer. Twenty-four experienced manual wheelchair users propelled at a self-selected speed on smooth, level tile and a dynamometer while kinetic data were collected using an instrumented wheel. A Pearson correlation test was used to examine the relationship between propulsion variables obtained on the dynamometer and the overground condition. Ensemble resultant force and moment curves were compared using cross-correlation and qualitative analysis of curve shape. User biomechanics were correlated (R ranging from 0.41 to 0.83) between surfaces. Overall, findings suggest that although the dynamometer does not perfectly emulate overground propulsion, wheelchair users were consistent with the direction and amount of force applied, the time peak force was reached, push angle, and their stroke frequency between conditions.

Evaluation of rolling resistance in manual wheelchair wheels and casters using drum-based testing.

PURPOSE: Rolling resistance is a drag force that increases the required propulsion force of manual wheelchair users (MWU) and increases the risk of upper extremity pain and injury. MATERIALS AND METHODS: To understand the influence of different design, environmental, and setup factors on rolling resistance (RR), a series of tests were performed on a range of wheels and casters using a drum-based equipment with the capability to measure RR forces. Independent factors were varied including load, camber, toe, speed, tire pressure, and surface, using ranges anticipated in the community. Combined factor testing of these factors was also completed to evaluate of RR changes due interactions of multiple factors. RESULTS: A default reference trial was used to verify repeatability throughout the 924 rear wheel trials and 255 caster trials. Toe angle and tire pressure were found to have large and exponential relationships to RR. Tire/caster type and surfaces are significant influencers but have no specific relationship to RR. Load had a direct linear relationship to RR whereas camber and speed had a relatively small impact on RR. Pneumatic tires had lower rolling resistance compared to airless inserts, solid mag wheels and knobby tires. Combined factor testing revealed a linear additive effect of individual factors. Statistical analysis revealed that tire/caster type is a covariate to all of the results and statistical differences (p < 0.01) were found for toe, tire/caster type, tire pressure, surfaces and load. CONCLUSIONS: Factors act in a cumulative manner to impact RR and need to be monitored in device design, development, issuance, and maintenance.Implications for RehabilitationFirst comprehensive study of MWC RR showing the effects of individual and combined factors.Highlights the direct importance of tire and caster selection.

Preliminary feasibility and acute physiological effects of a single session of upper limb vibration training for persons with spinal cord injury.

CONTEXT: Strong upper limb musculature is essential for persons with spinal cord injury (SCI) to operate a manual wheelchair and live independently. Targeted upper limb vibration may be a viable exercise modality to build muscle efficiently while eliminating some of the barriers associated with exercise for persons with SCI. OBJECTIVE: The purpose of this study was to assess preliminary feasibility of completing a single exercise session of upper limb vibration and compare the acute physiological effects to a single session of standard dumbbell resistance exercise. METHODS: Individuals with SCI performed seven upper limb exercises (1) isometrically using a vibrating dumbbell at 30 Hz for 60 s (n = 22) and (2) using a standard isotonic resistance protocol (n = 15). RESULTS: Nineteen (86.4%) of 22 participants were able to perform all vibration exercises at 30 Hz but hold time success rates varied from 33% (side flies and front raises) to 95% (internal rotation). No significant differences were found between vibration exercise and standard resistance protocol for blood lactate, power output, and heart rate (P > 0.05). Perceptions of the training were positive, with most participants (>70%) expressing interest to train with vibration in the future. CONCLUSIONS: Vibration training was not feasible for all participants, suggesting an individualized approach to starting weight and progression may be necessary. Similar acute physiological changes were seen between vibration exercise and standard resistance protocol, suggesting they could have similar benefits. Additional research is needed to determine if vibration exercise is feasible and beneficial to incorporate into a long-term training program.