Wheelchair Activities Research Articles

Reliability and validity of portable dynamometers in testing shoulder and shoulder girdle strength: A systematic review

Introduction
 The prevalence of shoulder pain is high in overhead athletes and in wheelchair users with a spinal cord injury (SCI). Especially in the latter, shoulder pain can have detrimental consequences for an individual's mobility, participation, and quality of life. Shoulder problems have been associated with high and/or repetitive loads induced by for example overhead activities, as well as manual wheelchair activities (Leong et al., 2019; Morrow et al., 2011). Modifiable risk factors for shoulder pain are related to the capacity of the shoulder musculature and include the relative strength or lack of force in certain shoulder muscles (Mulroy et al., 2015). Although isokinetic dynamometers are considered the gold standard in assessing muscle strength, they are typically not available in a therapy or training setting. Strength measurements with portable dynamometers offer a more feasible and financially affordable alternative. To assess changes in muscle strength over time, reliable and valid shoulder and shoulder girdle muscle strength tests are required. Therefore, the aim of this study was to identify validated and reliable portable dynamometer protocols to assess changes in shoulder strength in the general population and wheelchair users with SCI over time.
 Methods
 A literature search was performed with defined terms from the three main concepts “shoulder joint”, “strength testing” and “reproducibility of results”. The electronic search strategy was developed with the help of a librarian and adapted for the following databases: PubMed (Medline), Cochrane Library (Central register of controlled trials), Web of Science (Core Collection), CINAHL. The population of interest was the general population (≥ 18 years) with and without shoulder pain with a special focus on wheelchair users with SCI. Title and abstract screening, full-text screening, quality assessment and data extraction was performed using Covidence.org. For quality assessment selected boxes from the “COSMIN Risk of Bias tool” were used. Data extraction was performed by two independent authors. The main outcome measures extracted where test-retest reliability (intraclass correlation coefficient, standard error of measurement and minimum detectable difference) and concurrent validity (intraclass correlation coefficient).
 Results
 Trough systematic search 8,020 studies were identified for screening. Initially 2,267 were excluded as duplicates and 5,647 were excluded for not meeting the inclusion criteria. 106 full-texts have been screened. As data extraction is ongoing the results of reliability and validity of portable dynamometer in testing shoulder strength will be presented at the conference.
 Discussion/Conclusion
 As data extraction is ongoing the discussion and conclusion will be presented at the conference.
 References
 Leong, H. T., Fu, S. C., He, X., Oh, J. H., Yamamoto, N., & Yung, S. H. P. (2019). Risk factors for rotator cuff tendinopathy: A systematic review and meta-analysis. Journal of Rehabilitation Medicine, 51(9), 627-637. https://doi.org/10.2340/16501977-2598
 Morrow, M. M. B., Kaufman, K. R., An, K.-N. (2011). Scapula kinematics and associated impingement risk in manual wheelchair users during propulsion and a weight relief lift. Clinical Biomechanics, 26(4), 352-357. https://doi.org/10.1016/j.clinbiomech.2010.12.001
 Mulroy, S. J., Hatchett, P., Eberly, V. J., Lighthall Haubert, L., Conners, S., & Requejo, P. S. (2015). Shoulder strength and physical activity predictors of shoulder pain in people with paraplegia from spinal injury: Prospective cohort study. Physical Therapy, 95(7), 1027-1038. https://doi.org/10.2522/ptj.20130606

Potential limitations of measuring ambulatory activity of part-time wheelchair users: a comparative study of two research grade activity monitors

Objective. Research grade activity monitors such as the StepWatch Activity Monitor (SAM) and Actigraph have been shown to be highly accurate for the assessment of ambulatory activity, but some individuals function in the community using a combination of both walking and wheelchair activity. The purpose of this study was to assess the accuracy of the SAM and Actigraph at not detecting ambulatory activity, during wheelchair activities at two intensity levels. Approach. Two independent cohorts were tested while simultaneously wearing a SAM and Actigraph on the ankle. Group 1 consisted of twelve adults performing a six-minute push test (6MPT). Group 2 were eighteen members of an adolescent wheelchair basketball team tested during a scrimmage/practice and regional tournament. Visual observation was used to confirm the number of ambulatory steps taken during testing was zero. Main results. The average number of ‘steps’ detected during a 6MPT was 19 ± 25 (range: 0–85) with the Actigraph. No ‘steps’ were detected using the SAM in Group 1. In Group 2, the average ‘step’ count during basketball practice was 1421 ± 750 (range: 612–2798) using the Actigraph and 1363 ± 1238 (range: 84–3462) using the SAM, and correlated with playing time, despite the leg/ankle being strapped down. Similar findings were observed during the wheelchair basketball regional tournament. Significance. Caution should be heeded when utilizing these activity monitors in individuals with disabilities who participate in wheelchair sports. Additional written activity logs should be used to exclude periods of time during which high acceleration wheelchair sporting activity occurs, or study participants should be fully educated in removing the activity monitors during non-ambulatory wheelchair sports.

Physical activity levels and shoulder pain in wheelchair users during COVID-19 restrictions

BackgroundManual wheelchair users are at high risk of developing shoulder pain. However, it is not known if restrictions to limit the spread of the COVID-19 virus affected physical activity, wheelchair use and shoulder pain. ObjectiveThe aim of the study is to determine whether COVID-19 related restrictions caused changes in physical activity levels and the presence of shoulder pain in persons who use a wheelchair. MethodsManual wheelchair users completed a survey about the presence and severity of shoulder pain in a cross-sectional study design. Participants completed the Leisure Time Physical Activity Questionnaire and were asked about daily wheelchair activity before and during lockdown. A logistic regression examined the relationship between increase in shoulder pain severity and change in activity levels. ResultsSixty respondents were included for analysis. There was no significant change in physical activity during lockdown. There was a significant reduction in number of hours of daily wheelchair use and number of chair transfers during lockdown. Of the respondents, 67% reported having shoulder pain and 22% reported their shoulder pain becoming more severe during lockdown. No significant relationship was observed between the change in activity levels and increasing severity of shoulder pain. ConclusionRestrictions to reduce the spread of the COVID-19 virus resulted in no changes in physical activity levels in a sample of adult manual wheelchair users; however, there was a reduced time using a wheelchair each day and fewer chair transfers. The changes in wheelchair activities were not related to the worsening of shoulder pain.

A Scoping Review on Shoulder Injuries of Wheelchair Tennis Players: Potential Risk-Factors and Musculoskeletal Adaptations.

Wheelchair tennis players are prone to develop shoulder injuries, due to the combination of wheelchair propulsion, overhead activities and daily wheelchair activities. A methodical literature search was conducted to identify articles on shoulder complaints in wheelchair tennis, wheelchair sports and tennis. The aims were to identify (1) type of shoulder complaints; (2) possible risk factors for the development of shoulder injuries; (3) musculoskeletal adaptations in the shoulder joint in wheelchair tennis players. Fifteen papers were included in this review, five on wheelchair tennis, three on wheelchair sports and seven on tennis. Type of shoulder complaints were acromioclavicular pathology, osteoarthritic changes, joint effusion and rotator cuff tears. Possible risk factors for the development of shoulder injuries in wheelchair tennis are overhead movements, repetitive activation of the anterior muscle chain and internal rotators, as well as a higher spinal cord injury level. Muscular imbalance with higher values for the internal rotators, increase in external range of motion, decrease in internal range of motion and reduced total arc of motion were the most common proposed musculoskeletal adaptations due to an unbalanced load. These presented risk factors and musculoskeletal adaptations might help researchers, coaches and wheelchair tennis players to prevent shoulder injuries.

Accuracy of Heart Rate Measurement by the Fitbit Charge 2 During Wheelchair Activities in People With Spinal Cord Injury: Instrument Validation Study.

BackgroundHeart rate (HR) is an important and commonly measured physiological parameter in wearables. HR is often measured at the wrist with the photoplethysmography (PPG) technique, which determines HR based on blood volume changes, and is therefore influenced by blood pressure. In individuals with spinal cord injury (SCI), blood pressure control is often altered and could therefore influence HR accuracy measured by the PPG technique.ObjectiveThe objective of this study is to investigate the HR accuracy measured with the PPG technique with a Fitbit Charge 2 (Fitbit Inc) in wheelchair users with SCI, how the activity intensity affects the HR accuracy, and whether this HR accuracy is affected by lesion level.MethodsThe HR of participants with (38/48, 79%) and without (10/48, 21%) SCI was measured during 11 wheelchair activities and a 30-minute strength exercise block. In addition, a 5-minute seated rest period was measured in people with SCI. HR was measured with a Fitbit Charge 2, which was compared with the HR measured by a Polar H7 HR monitor used as a reference device. Participants were grouped into 4 groups—the no SCI group and based on lesion level into the <T5 (midthoracic and lower) group, T5-T1 (high-thoracic) group, and >T1 (cervical) group. Mean absolute percentage error (MAPE) and concordance correlation coefficient were determined for each group for each activity type, that is, rest, wheelchair activities, and strength exercise.ResultsWith an overall MAPEall lesions of 12.99%, the accuracy fell below the standard acceptable MAPE of –10% to +10% with a moderate agreement (concordance correlation coefficient=0.577). The HR accuracy of Fitbit Charge 2 seems to be reduced in those with cervical lesion level in all activities (MAPEno SCI=8.09%; MAPE<T5=11.16%; MAPET1−T5=10.5%; and MAPE>T1=20.43%). The accuracy of the Fitbit Charge 2 decreased with increasing intensity in all lesions (MAPErest=6.5%, MAPEactivity=12.97%, and MAPEstrength=14.2%).ConclusionsHR measured with the PPG technique showed lower accuracy in people with SCI than in those without SCI. The accuracy was just above the acceptable level in people with paraplegia, whereas in people with tetraplegia, a worse accuracy was found. The accuracy seemed to worsen with increasing intensities. Therefore, high-intensity HR data, especially in people with cervical lesions, should be used with caution.

Eye Movement Signal Classification for Developing Human-Computer Interface Using Electrooculogram.

Human-computer interfaces (HCI) allow people to control electronic devices, such as computers, mouses, wheelchairs, and keyboards, by bypassing the biochannel without using motor nervous system signals. These signals permit communication between people and electronic-controllable devices. This communication is due to HCI, which facilitates lives of paralyzed patients who do not have any problems with their cognitive functioning. The major plan of this study is to test out the feasibility of nine states of HCI by using modern techniques to overcome the problem faced by the paralyzed. Analog Digital Instrument T26 with a five-electrode system was used in this method. Voluntarily twenty subjects participated in this study. The extracted signals were preprocessed by applying notch filter with a range of 50 Hz to remove the external interferences; the features were extracted by applying convolution theorem. Afterwards, extracted features were classified using Elman and distributed time delay neural network. Average classification accuracy with 90.82% and 90.56% was achieved using two network models. The accuracy of the classifier was analyzed by single-trial analysis and performances of the classifier were observed using bit transfer rate (BTR) for twenty subjects to check the feasibility of designing the HCI. The achieved results showed that the ERNN model has a greater potential to classify, identify, and recognize the EOG signal compared with distributed time delay network for most of the subjects. The control signal generated by classifiers was applied as control signals to navigate the assistive devices such as mouse, keyboard, and wheelchair activities for disabled people.

The Preliminary Criterion Validity of the Activ8 Activity Monitor to Measure Physical Activity in Youth Using a Wheelchair.

The aim of this study was to assess the criterion validity of the Activ8 to detect "active wheelchair use" and to distinguish 6 types of wheelchair activities using video recordings as a gold standard. Ten participants who use a manual wheelchair were participants in this study. Data of 2 participants were used for adapting the algorithm and data of 7 participants were used for assessing the criterion validity. Criterion validity for detecting "active wheelchair use" had a relative time difference of 7.4%, agreement of 96%, sensitivity of 98.3%, and positive predictive value of 90%. Results for distinguishing 6 types of wheelchair activities had an agreement of 73%, sensitivity of 67.1%, and positive predictive value of 65.5%. The Activ8 is able to detect "active wheelchair use" in youth using a manual wheelchair. Further development of the algorithm is necessary to distinguish between different types of wheelchair activities.

A Comparison Between Conventional and User-Intention-Based Adaptive Pushrim-Activated Power-Assisted Wheelchairs.

Pushrim-activated power-assisted wheel (PAPAW) users ideally require different levels of assistance depending on activity and preference. Therefore, it is important to design and develop adaptive PAPAW controllers to account for these differences. The main objective of this work was to integrate a user intention estimation framework into a PAPAW and develop personalized adaptive controllers. We performed experiments to gather kinetics of wheelchair propulsion for a variety of daily life wheelchair activities. The propulsion characteristics (i.e., pushrim forces) were used to train intention estimation models and characterize implicit user intentions when performing daily life wheelchair maneuvers. These intentions included moving straight forward, performing a right/left turn, and braking. The intention estimation framework, based on random forest classification algorithms and kinetic features, was implemented and tested in our laboratory-developed PAPAW. This computationally efficient framework was successfully implemented and tested for each participant in real-time. Our results revealed that the real-time user intention predictions were similar to the offline models. The power-assist ratio of each wheel was adjusted based on which user intention was identified. Data collected from four participants provided evidence regarding the effectiveness of using adaptive intention-based controllers. For instance, the propulsion effort was significantly reduced when using an adaptive PAPAW controller. Subjective views of participants regarding the workload of wheelchair propulsion (e.g., physical/cognitive effort) were also gathered. Our findings suggest that rankings of different controllers varied among different participants and across different wheelchair maneuvers, indicating the need for customized adaptive controllers to fit different users' activities and preferences.

A Comparison Between Conventional and Terrain-Specific Adaptive Pushrim-Activated Power-Assisted Wheelchairs.

Pushrim-activated power-assisted wheels (PAPAWs) are assistive technologies that provide on-demand propulsion assistance to wheelchair users. In this study, we aimed to develop an adaptive PAPAW controller that responds effectively to changes in environmental conditions (e.g., type of surface or terrain). Experiments were conducted to collect kinematics of wheelchair motion using a frame-mounted inertial measurement unit (IMU) while performing a variety of wheelchair activities on different indoor/outdoor terrains. Statistical characteristics of velocity and acceleration measurements were extracted and used to develop a terrain classification framework to identify certain indoor and outdoor terrains. The terrain classification framework, based on random forest classification algorithms and kinematic features, was implemented and tested in our laboratory-developed PAPAW. This computationally efficient terrain classification framework was successfully implemented and tested in real-time. The power-assist ratio of each wheel was adjusted based on the type of terrain (e.g., more assistance was provided on outdoor terrains). Our findings revealed that propulsion effort (e.g., peak input torque) on asphalt was significantly reduced when using adaptive controllers compared to conventional PAPAW controllers. In addition, subjective views of participants regarding the workload of wheelchair propulsion (e.g., physical/cognitive effort) supported the positive effects of adaptive PAPAW controllers. We believe that the adoption of terrain-specific adaptive controllers has the potential to improve the accessibility of outdoor terrains and to prevent or delay upper extremity joint degeneration or pain.

Validity of Two Wheelchair-Mounted Devices for Estimating Wheelchair Speed and Distance Traveled.

This study evaluated the validity of two wheelchair-mounted devices-the Cateye® and Wheeler-for monitoring wheelchair speed and distance traveled. Speed estimates were validated against a calibrated treadmill at speeds from 1.5 to 10km/hr. Twenty-five wheelchair users completed a course of known distance comprising a sequence of everyday wheelchair activities. Speed estimate validity was very good (mean absolute percentage error ≤ 5%) for the Wheeleri at all speeds and for the Cateye at speeds >3km/hr but not speeds <3km/hr (mean absolute percentage error > 20%). Wheeleri distance estimates were good (mean absolute percentage error < 10%) for linear pushing activities and general maneuvering but poor for confined-space maneuvering. Cateye estimates were good for continuous linear propulsion but poor for discontinuous pushing and maneuvering (both general and confined space). Both devices provided valid estimates of speed and distance for typical wheelchair-based exercise activities. However, the Wheeleri provided more accurate estimates of speed and distance during typical everyday wheelchair activities.

Classifying trunk strength impairment according to the activity limitation caused in wheelchair rugby performance.

International Federations in Paralympic sports should develop evidence-based classification, based on the relative strength of association between impairment and activities that determine sport-specific performance. The purpose of the current study was to assess the relationship between trunk strength impairment and three activities that determine performance in wheelchair rugby, and to determine whether this relationship supports the concept of "natural classes." Trunk muscle strength and three determinants of performance were assessed in 27 athletes. The correlations between lateral trunk muscle strength and the determinant tilting the chair, and between forward trunk muscle strength and the determinants 1m acceleration and sprint momentum were calculated. To group athletes based on impairment, K-means cluster analysis was used to group athletes according to how much trunk muscle strength affected the activities. There were significant, moderate to strong correlations between left-right strength and chair tilting (r=.50), between forward strength and 1m acceleration (r=.59), and between forward strength and sprint momentum (r=.79). Cluster analysis indicated at least one cut-point in performance with a decrease in impairment in all three wheelchair activities, supporting the concept of "natural classes."

Development and user validation of driving tasks for a power wheelchair simulator

Mobility is important for participation in daily activities and a power wheelchair (PW) can improve quality of life of individuals with mobility impairments. A virtual reality simulator may be helpful in complementing PW skills training, which is generally seen as insufficient by both clinicians and PW users. To this end, specific, ecologically valid activities, such as entering an elevator and navigating through a shopping mall crowd, have been added to the McGill wheelchair (miWe) simulator through a user-centred approach.Purpose: The objective of this study was to validate the choice of simulated activities in a group of newly trained PW users.Methods: We recruited 17 new PW users, who practiced with the miWe simulator at home for two weeks. They then related their experience through the Short Feedback Questionnaire, the perceived Ease of Use Questionnaire, and semi-structured interviews.Results: Participants in general greatly appreciated their experience with the simulator. During the interviews, this group made similar comments about the activities as our previous group of expert PW users had done. They also insisted on the importance of realism in the miWe activities, for their use in training.Discussion: A PW simulator may be helpful if it supports the practice of activities in specific contexts (such as a bathroom or supermarket), to complement the basic skills training received in the clinic (such as driving forward, backward, turning, and avoiding obstacles).Implications for RehabilitationNew power wheelchair users appreciate practicing on a virtual reality simulator and find the experience useful when the simulated diving activities are realistic and ecologically valid.User-centred development can lead to simulated power wheelchair activities that adequately capture everyday driving challenges experienced in various environmental contexts.

Validation of an activity monitor for children who are partly or completely wheelchair-dependent.

BackgroundChildren who are wheelchair-dependent are at risk for developing unfavorable physical behavior; therefore, assessment, monitoring and efforts to improve physical behavior should start early in life. VitaMove is an accelerometer-based activity monitor and can be used to detect and distinguish different categories of physical behavior, including activities performed in a wheelchair and activities using the legs. The purpose of this study was to assess the validity of the VitaMove activity monitor to quantify physical behavior in children who are partly or completely wheelchair-dependent.MethodsTwelve children with spina bifida (SB) or cerebral palsy (CP) (mean age, 14 ± 4 years) performed a series of wheelchair activities (wheelchair protocol) and, if possible, activities using their legs (n = 5, leg protocol). Activities were performed at their own home or school. In children who were completely wheelchair-dependent, VitaMove monitoring consisted of one accelerometer-based recorder attached to the sternum and one to each wrist. For children who were partly ambulatory, an additional recorder was attached to each thigh. Using video-recordings as a reference, primary the total duration of active behavior, including wheeled activity and leg activity, and secondary agreement, sensitivity and specificity scores were determined.ResultsDetection of active behaviour with the VitaMove activity monitor showed absolute percentage errors of 6% for the wheelchair protocol and 10% for the leg protocol. For the wheelchair protocol, the mean agreement was 84%, sensitivity was 80% and specificity was 85%. For the leg protocol, the mean agreement was 83%, sensitivity was 78% and specificity was 90%. Validity scores were lower in severely affected children with CP.ConclusionsThe VitaMove activity monitor is a valid device to quantify physical behavior in children who are partly or completely wheelchair-dependent, except for severely affected children and for bicycling.

The relationship between independent transfer skills and upper limb kinetics in wheelchair users.

Transfers are one of the most physically demanding wheelchair activities. The purpose of this study was to determine if using proper transfer skills as measured by the Transfer Assessment Instrument (TAI) is associated with reduced loading on the upper extremities. Twenty-three wheelchair users performed transfers to a level-height bench while a series of forces plates, load cells, and a motion capture system recorded the biomechanics of their natural transferring techniques. Their transfer skills were simultaneously evaluated by two study clinicians using the TAI. Logistic regression and multiple linear regression models were used to determine the relationships between TAI scores and the kinetic variables on both arms across all joints. The results showed that the TAI measured transfer skills were closely associated with the magnitude and timing of joint moments (P < .02, model R2 values ranged from 0.27 to 0.79). Proper completion of the skills which targeted the trailing arm was associated with lower average resultant moments and rates of rise of resultant moments at the trailing shoulder and/or elbow. Some skills involving the leading side had the effect of increasing the magnitude or rate loading on the leading side. Knowledge of the kinetic outcomes associated with each skill may help users to achieve the best load-relieving effects for their upper extremities.

Load on the shoulder complex during wheelchair propulsion and weight relief lifting

BackgroundThis study focuses on the relationship between overuse in association with wheelchair activities of daily living and risks for osteoarthrosis in the acromioclavicular and sternoclavicular joints. The aim is to quantify the joint moments and joint reaction forces in all three joints of the shoulder complex during wheelchair-related activities of daily living. MethodsA convenience sample of 17 subjects performed two tasks (wheelchair propulsion and weight relief lifting). Three-dimensional kinematics and kinetics were measured and position and force data were used as input for a musculoskeletal model of the arm and shoulder. Output variables of the model were the moments and the joint reaction forces on the sternoclavicular, acromioclavicular and glenohumeral joints. FindingsMoments on the sternoclavicular joint were higher than on the acromioclavicular and glenohumeral joint, but the joint reaction forces on the sternoclavicular and acromioclavicular joints were only one third of those on the glenohumeral joint (peak forces around 96N compared to 315N for wheelchair propulsion and around 330N compared to 1288N for weight relief lifting). InterpretationBased on the results found in this study, net joint moments are likely a better measure to describe the load on the acromioclavicular and sternoclavicular joints due to the passive stabilization. Prospective studies on wheelchair overuse injuries should also look at the acromioclavicular and sternoclavicular joints since the load of wheelchair tasks might be a risk factor for osteoarthrosis in these joints.

A Compendium of Energy Costs of Physical Activities for Individuals Who use Manual Wheelchairs

The purpose of this study was to develop a compendium of wheelchair-related physical activities. To accomplish this, we conducted a systematic review of the published energy costs of activities performed by individuals who use wheelchairs. A total of 266 studies were identified by a literature search using relevant keywords. Inclusion criteria were studies utilizing individuals who routinely use a manual wheelchair, indirect calorimetry as the criterion measurement, energy expenditure expressed as METs or VO₂, and physical activities typical of wheelchair users. Eleven studies met the inclusion criteria. A total of 63 different wheelchair activities were identified with energy expenditure values ranging from 0.8 to 12.5 kcal·kg-1·hr-1. The energy requirements for some activities differed between individuals who use wheelchairs and those who do not. The compendium of wheelchair-related activities can be used to enhance scoring of physical activity surveys and to promote the benefits of activity in this population.

Wheelchair-Related Falls in Veterans With Spinal Cord Injury Residing in the Community: A Prospective Cohort Study

Nelson AL, Groer S, Palacios P, Mitchell D, Sabharwal S, Kirby RL, Gavin-Dreschnack D, Powell-Cope G. Wheelchair-related falls in veterans with spinal cord injury residing in the community: a prospective cohort study. Objectives (1) To determine the incidence of wheelchair falls and fall-related injuries in persons with spinal cord injury (SCI) living in the community. (2) To predict wheelchair-related falls and associated injuries from specific parameters including characteristics of the wheelchair user, wheelchair type and features, health care practices, wheelchair activities, and physical environment. Design This prospective cohort study followed participants monthly over 1 year; data were collected through surveys, interviews, performance testing, observation, and medical records. Setting Three Veterans' Administration hospitals. Participants Convenience sample of community-dwelling persons with SCI who used a wheelchair as their primary means of mobility (N=702). Interventions Not applicable. Main Outcome Measures Self-reports of wheelchair falls and fall-related injuries, Wheelchair User Characteristics Survey, Health Status Checklist, Health-Related Behaviors, Zuckerman Sensation Seeking Scale, Wheelchair and Equipment-Related Behaviors, Wheelchair Characteristics, Wheelchair Skills Test, and Physical Environment Assessment. Results Of the 659 subjects who completed the study, 204 participants (31%) reported 553 fall events, and 95 subjects (14%) were injured as a result of wheelchair falls. A logistic regression model for predicting wheelchair falls identified 6 significant risk factors: pain in previous 2 months, alcohol abuse, greater motor function, history of previous fall, fewer SCI years, and shorter length of wheelchair. Eighty-two percent of the variance for wheelchair fall events was explained by these 6 variables. A logistic regression model for predicting injurious falls identified 4 significant risk factors: pain in previous 2 months, greater motor function, history of previous fall, and inaccessible home entrance. These 4 factors were able to explain 81% of the variance for injurious falls. Conclusions This is the first study to determine the incidence of wheelchair-related falls in community-dwelling people with SCI who use a wheelchair. Results indicate the incidence of falls was 31% and injurious falls was 14%. Those at greatest risk can be predicted from some readily available information regarding their clinical status, wheelchair features, and home environment.

Shoulder model validation and joint contact forces during wheelchair activities

Chronic shoulder impingement is a common problem for manual wheelchair users. The loading associated with performing manual wheelchair activities of daily living is substantial and often at a high frequency. Musculoskeletal modeling and optimization techniques can be used to estimate the joint contact forces occurring at the shoulder to assess the soft tissue loading during an activity and to possibly identify activities and strategies that place manual wheelchair users at risk for shoulder injuries. The purpose of this study was to validate an upper extremity musculoskeletal model and apply the model to wheelchair activities for analysis of the estimated joint contact forces. Upper extremity kinematics and handrim wheelchair kinetics were measured over three conditions: level propulsion, ramp propulsion, and a weight relief lift. The experimental data were used as input to a subject-specific musculoskeletal model utilizing optimization to predict joint contact forces of the shoulder during all conditions. The model was validated using a mean absolute error calculation. Model results confirmed that ramp propulsion and weight relief lifts place the shoulder under significantly higher joint contact loading than level propulsion. In addition, they exhibit large superior contact forces that could contribute to impingement. This study highlights the potential impingement risk associated with both the ramp and weight relief lift activities. Level propulsion was shown to have a low relative risk of causing injury, but with consideration of the frequency with which propulsion is performed, this observation is not conclusive.

Mechanical Load on the Upper Extremity During Wheelchair Activities

Mechanical Load on the Upper Extremity During Wheelchair Activities

Mechanical Load on the Upper Extremity During Wheelchair Activities

van Drongelen S, van der Woude LH, Janssen TW, Angenot EL, Chadwick EK, Veeger DH. Mechanical load on the upper extremity during wheelchair activities. Arch Phys Med Rehabil 2005;86:1214–20. Objective To determine the net moments on the glenohumeral joint and elbow joint during wheelchair activities. Design Kinematics and external forces were measured during wheelchair activities of daily living (level propulsion, riding on a slope, weight-relief lifting, reaching, negotiating a curb) and processed in an inverse dynamics biomechanic model. Setting Biomechanics laboratory. Participants Five able-bodied subjects, 8 subjects with paraplegia, and 4 subjects with tetraplegia. Interventions Not applicable. Main Outcome Measure Net moments on the glenohumeral joint and elbow joint. Results Peak shoulder and elbow moments were significantly higher for negotiating a curb and weight-relief lifting than for reaching, level propulsion, and riding on a slope. Overall, the elbow extension moments were significantly lower for subjects with tetraplegia than for those with paraplegia. Conclusions The net moments during weight-relief lifting and negotiating a curb were high when compared with wheelchair propulsion tasks. Taking the effect of frequency and duration into account, these loads might imply a considerable risk for joint damage in the long term.