Valid detection of self-propelled wheelchair driving with two accelerometers

Technologies measuring manual wheelchair propulsion metrics: a scoping review

The aim of this review is to investigate existing and developing technologies assessing metrics of manual wheelchair propulsion. A scoping review of scientific and gray literature was performed. Five databases were searched - Medline, Scopus, CINAHL, Institute of Electrical and Electronics Engineers (IEEE), and Embase. The 38 retained articles identified 27 devices categorized into accelerometers, wheelchair-mounted devices, instrumented wheels, and wearables. The devices included in this review can be used by manual wheelchair users to monitor propulsion effort and activity goals, by clinicians to assess rehabilitation programs, and to inform and guide future research. The findings support a need for further research into the development of custom algorithms for manual wheelchair user populations as well as further validation in broader free-living environments with equitable participant populations.

Sudden stop detection and automatic seating support with neural stimulation during manual wheelchair propulsion

Objective: Wheelchair safety is of great importance since falls from wheelchairs are prevalent and often have devastating consequences. We developed an automatic system to detect destabilizing events during wheelchair propulsion under real-world conditions and trigger neural stimulation to stiffen the trunk to maintain seated postures of users with paralysis.Design: Cross-over interventionSetting: Laboratory and community settingsParticipants: Three able-bodied subjects and three individuals with SCI with previously implanted neurostimulation systemsInterventions: An algorithm to detect wheelchair sudden stops was developed. This was used to randomly trigger trunk extensor stimulation during sudden stops eventsOutcome Measures: Algorithm success and false positive rates were determined. SCI users rated each condition on a seven-point Usability Rating Scale to indicate safety.Results: The system detected sudden stops with a success rate of over 93% in community settings. When used to trigger trunk neurostimulation to ensure stability, the implant recipients consistently reported feeling safer (P<.05 for 2/3 subjects) with the system while encountering sudden stops as indicated by a 1-3 point change in safety rating.Conclusion: These preliminary results suggest that this system could monitor wheelchair activity and only apply stabilizing neurostimulation when appropriate to maintain posture. Larger scale, unsupervised and longer-term trials at home and in the community are indicated. This system could be generalized and applied to individuals without an implanted stimulation by utilizing surface stimulation, or by actuating a mechanical restraint when necessary, thus allowing unrestricted trunk movements and only restraining the user when necessary to ensure safety.Trial Registration: NCT01474148.

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.

Detecting clinical practice guideline-recommended wheelchair propulsion patterns with wearable devices following a wheelchair propulsion intervention

Wheelchair propulsion interventions typically teach manual wheelchair users to perform wheelchair propulsion biomechanics as recommended by the Clinical Practice Guidelines (CPG). Outcome measures for these interventions are primarily laboratory based. Discrepancies remain between manual wheelchair propulsion (MWP) in laboratory-based examinations and propulsion in the real-world. Current developments in machine learning (ML) allow for monitoring of MWP in the real world. In this study, we collected data from participants enrolled in two wheelchair propulsion interventions, then built an ML algorithm to distinguish CPG recommended MWP patterns from non-CPG-recommended patterns. Eight primary manual wheelchair users did not initially follow CPG recommendations but learned and performed CPG propulsion after the interventions. Participants each wore two inertial measurement units as they propelled their wheelchairs on a roller system, indoors overground, and outdoors. ML models were trained to classify propulsion patterns as following the CPG or not following the CPG. Video recordings were used for reference. For indoor detection, we found that a subject-independent model was able to achieve 85% accuracy. For outdoor detection, we found that the subject-independent model achieved 75.4% accuracy. These results provide further evidence that CPG and non-CPG-recommended MWP patterns can be predicted with wearable sensors using an ML algorithm.

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

PURPOSE

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.

METHODS

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.

RESULTS

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%.

CONCLUSIONS

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.

Validity of the Apple Watch® for monitoring push counts in people using manual wheelchairs

Objective: A recent Apple Watch® activity-monitoring innovation permits manual wheelchair users to monitor daily push counts. This study evaluated the validity of the Apple Watch® push count estimate.Design: Criterion validity.Setting: Southern Finland and Southeast Queensland, Australia.Participants: Twenty-six manual wheelchair users from Finland and Australia were filmed completing a standardized battery of activities while wearing the Apple Watch® (dominant wrist).Outcome Measures: Wheelchair pushes as determined by the Apple Watch® were compared to directly observed pushes.Results: Agreement between Apple Watch® push counts and directly observed pushes was evaluated using Intraclass correlation coefficients (ICC), Pearson correlations and Bland-Altman analyses. Apple Watch® pushes and directly observed push counts were strongly correlated (ICC = 0.77, P < 0.01) (r = 0.84, P < 0.01). Bland Altman plots indicated that the Apple Watch® underestimated push counts (M = -103; 95% ULoA = 217; LLoA = -423 pushes). Mean absolute percentage error was 13.5% which is comparable to studies evaluating agreement between pedometer-based step counts and directly observed steps.Conclusion: Apple Watch® push-count estimates are acceptable for personal, self-monitoring purposes and for research entailing group-level analyses, but less acceptable where accurate push-count measures for an individual is required.

Systematic review on the application of wearable inertial sensors to quantify everyday life motor activity in people with mobility impairments

BACKGROUND

Recent advances in wearable sensor technologies enable objective and long-term monitoring of motor activities in a patient's habitual environment. People with mobility impairments require appropriate data processing algorithms that deal with their altered movement patterns and determine clinically meaningful outcome measures. Over the years, a large variety of algorithms have been published and this review provides an overview of their outcome measures, the concepts of the algorithms, the type and placement of required sensors as well as the investigated patient populations and measurement properties.

METHODS

A systematic search was conducted in MEDLINE, EMBASE, and SCOPUS in October 2019. The search strategy was designed to identify studies that (1) involved people with mobility impairments, (2) used wearable inertial sensors, (3) provided a description of the underlying algorithm, and (4) quantified an aspect of everyday life motor activity. The two review authors independently screened the search hits for eligibility and conducted the data extraction for the narrative review.

RESULTS

Ninety-five studies were included in this review. They covered a large variety of outcome measures and algorithms which can be grouped into four categories: (1) maintaining and changing a body position, (2) walking and moving, (3) moving around using a wheelchair, and (4) activities that involve the upper extremity. The validity or reproducibility of these outcomes measures was investigated in fourteen different patient populations. Most of the studies evaluated the algorithm's accuracy to detect certain activities in unlabeled raw data. The type and placement of required sensor technologies depends on the activity and outcome measure and are thoroughly described in this review. The usability of the applied sensor setups was rarely reported.

CONCLUSION

This systematic review provides a comprehensive overview of applications of wearable inertial sensors to quantify everyday life motor activity in people with mobility impairments. It summarizes the state-of-the-art, it provides quick access to the relevant literature, and it enables the identification of gaps for the evaluation of existing and the development of new algorithms.

The Effects of a Patient and Provider Co-Developed, Behavioral Physical Activity Intervention on Physical Activity, Psychosocial Predictors, and Fitness in Individuals with Spinal Cord Injury: A Randomized Controlled Trial

BACKGROUND

Physical activity (PA) interventions in people with spinal cord injury (SCI) have been limited by a shortage of (1) evidence for sufficient increases in unsupervised PA to improve aerobic fitness and (2) stakeholder involvement in intervention design.

OBJECTIVES

This study examined the effects of a theory-based PA intervention, developed in collaboration with nearly 300 stakeholders, on PA levels, aerobic fitness, and psychosocial predictors of PA among individuals with SCI.

METHODS

A randomized controlled trial (RCT) was conducted with 28 men and women with chronic SCI (age 45.0 ± 11.5 years, years post-injury 16.4 ± 12.4). Participants randomized to the intervention group (n = 14) received an introductory personal training session followed by eight weekly 15-min PA behavioral coaching sessions per week. PA was assessed using self-report and accelerometers. Aerobic fitness and psychosocial predictors of exercise were evaluated using an incremental exercise test and survey methods, respectively.

RESULTS

At post-intervention, controlling for baseline, the intervention group showed fivefold greater self-reported moderate to vigorous physical activity [mean difference 247.9 min/day; 95% confidence interval (CI) 92.8-403.1; p = 0.026, d = 1.04], 17% greater accelerometer-measured PA (mean difference 3.9 × 10⁵ vector magnitude counts; 95% CI 1.1 × 10⁴-7.7 × 10⁵; p = 0.014, d = 0.31), and 19% higher peak oxygen uptake (VO_2Peak; mean difference 0.23 L/min; 95% CI 0.12-0.33; p < 0.001, d = 0.54) compared with the control group. Mean values of psychosocial predictors of PA were also significantly improved in the intervention group compared with controls.

CONCLUSION

To our knowledge, this co-created behavioral intervention produced the largest effect size to date for change in self-reported PA in an RCT involving people with physical disability. This is also the first RCT in people with SCI to demonstrate that a behavioral intervention can sufficiently increase unsupervised PA to improve aerobic fitness.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03111030, 12 April 2017, https://clinicaltrials.gov/ct2/show/NCT03111030?term=NCT03111030&rank=1 .

Instruments Measuring Physical Activity in Individuals Who Use a Wheelchair: A Systematic Review of Measurement Properties

OBJECTIVE

To systematically review the evidence evaluating validity or reliability of self-reported and device-based instruments, to measure physical activity (PA) in individuals who use a wheelchair, and to make recommendations for the selection of PA outcomes tools.

DATA SOURCES

PubMed, Embase, and CINAHL were systematically searched.

STUDY SELECTION

Studies reporting measurement properties of instruments to assess PA in individuals who use a wheelchair.

DATA EXTRACTION

The Consensus-Based Standards for the Selection of Health Status Measurement Instruments checklist was used to assess the methodological quality of the included studies. The measurement properties of instruments assessing PA were examined.

DATA SYNTHESIS

The search yielded 5341 records, 61 were considered relevant, 21 articles were included. A best evidence synthesis was performed on 9 studies including 4 self-reported instruments and 13 studies including 8 device-based instruments. One study evaluated both self-reported and device-based instruments. The overall methodological quality of all studies ranged from poor to excellent. Variable levels of evidence were found for both the validity and reliability for self-reported instruments and for criterion validity for device-based instruments.

CONCLUSIONS

The Physical Activity Scale for Individuals with Disabilities (PASIPD) and The Physical Activity Recall Assessment for People with Spinal Cord Injury (PARA-SCI) seem the most promising self-reported instruments for measuring the intensity of PA. Device-based instruments that can be used for measuring both the intensity and type of PA are the GENEActiv, Actigraph GT3X+, Actiheart, or the Physical Activity Monitor System (PAMS), showing moderate evidence for a positive rating of criterion validity. For measuring the type of PA, the PAMS and VitaMove are suitable, showing both good evidence for a positive rating of criterion validity.

Measuring Physical Activity in Spinal Cord Injury Using Wrist-Worn Accelerometers

OBJECTIVE

Our objective was to evaluate interunit agreement and construct validity of two activity monitors (Actiwatch Score and PRO-Diary) in people with and without spinal cord injury.

METHOD

Thirty-eight participants (19 with spinal cord injury; 19 age- and sex-matched controls; mean age = 49 yr) wore both monitors and completed tasks during one visit ranging in physical intensity. To compare activity by group and monitor, we conducted t tests. We assessed interunit agreement using intraclass correlations and Bland-Altman plots.

RESULTS

Both monitors demonstrated significantly different increasing physical activity levels with higher intensity tasks. Participants with spinal cord injury had similar activity counts within tasks compared with controls except for walking-wheeling. Agreement was high between monitors across tasks (interclass correlation coefficients = .78-.97).

CONCLUSION

Both monitors demonstrated good construct validity for measuring physical activity across activities and high agreement. Either monitor is appropriate to examine physical activity patterns in people with spinal cord injury.

Toward community-based wheelchair evaluation with machine learning methods

Introduction

Upper extremity pain among manual wheelchair users induces functional decline and reduces quality of life. Research has identified chronic overuse due to wheelchair propulsion as one of the factors associated with upper limb injuries. Lack of a feasible tool to track wheelchair propulsion in the community precludes testing validity of wheelchair propulsion performed in the laboratory. Recent studies have shown that wheelchair propulsion can be tracked through machine learning methods and wearable accelerometers. Better results were found in subject-specific machine learning method. To further develop this technique, we conducted a pilot study examining the feasibility of measuring wheelchair propulsion patterns.

Methods

Two participants, an experienced manual wheelchair user and an able-bodied individual, wore two accelerometers on their arms. The manual wheelchair user performed wheelchair propulsion patterns on a wheelchair roller system and overground. The able-bodied participant performed common daily activities such as cooking, cleaning, and eating.

Results

The support vector machine built from the wrist and arm acceleration of wheelchair propulsion pattern recorded on the wheelchair roller system predicted the wheelchair propulsion patterns performed overground with 99.7% accuracy. The support vector machine built from additional rotation data recorded overground predicted wheelchair propulsion patterns (F1 = 0.968).

Conclusions

These results further demonstrate the possibility of tracking wheelchair propulsion in the community.

Outcome Measures of Free-Living Activity in Spinal Cord Injury Rehabilitation

Purpose of Review

The purpose of this article was to describe the utilization of body worn activity monitors in the SCI population and discuss the challenges of using body worn sensors in rehabilitation research.

Recent Findings

Many activity monitor-based measures have been used and validated in the SCI population including stroke number, push frequency, upper limb activity counts and wheelchair propulsion distance measured from a sensor attached to the wheelchair.

Summary

The ability to accurately measure physical activity in the free-living environment using body-worn sensors has the potential to enhance the understanding of barriers to adequate activity and identify possible effective interventions. As the use of activity monitors used in SCI rehabilitation research continues to grow, care must be taken to overcome challenges related to participant adherence and data quality.

Exercise self-efficacy is weakly related to engagement in physical activity in persons with long-standing spinal cord injury

Aims: Many people with a long-standing spinal cord injury have an inactive lifestyle. Although exercise self-efficacy is considered a key determinant of engaging in exercise, the relationship between exercise self-efficacy and physical activity remains unclear. Therefore, this study examines the relationship between exercise self-efficacy and the amount of physical activity in persons with long-standing spinal cord injury.Methods: This cross-sectional study included 268 individuals (aged 28-65 years) with spinal cord injury ≥ 10 years and using a wheelchair. Physical activity was measured with the Physical Activity Scale for Individuals with Physical Disabilities. Exercise self-efficacy was assessed with the Spinal cord injury Exercise Self-Efficacy Scale. Univariate and multivariable regression analyses were performed to test for the association between exercise self-efficacy and physical activity, controlling for supposed confounders.Results: Univariate regression analysis revealed that exercise self-efficacy was significantly related to the level of daily physical activity (β = 0.05; 95% CI 0.04-0.07; 15% explained variance; p < 0.001). In multivariable regression analysis exercise self-efficacy remained, explaining a significant additional amount of the variance (2%; p < 0.001) of physical activity.Conclusion: Exercise-self efficacy is a weak but independent explanatory factor of the level of physical activity among persons with long-standing spinal cord injury. Longitudinal trials are needed to study the impact of interventions targeting an increase of exercise self-efficacy on the amount of physical activity performed.Implications for rehabilitationPre-intervention levels of exercise-self-efficacy might mediate the effectiveness of interventions that aim at increasing physical activities in people with a long-standing spinal cord injury.Enhancing exercise-self efficacy may improve levels of physical activity, even in people with a long-standing spinal cord injury.When it comes to enhancing physical activity, efforts to enhance non-structured daily physical activities such as household activities and gardening might be as important as efforts to enhance sports and other physical exercise.

Use of a Low-Cost, Chest-Mounted Accelerometer to Evaluate Transfer Skills of Wheelchair Users During Everyday Activities: Observational Study

Background

Transfers are an important skill for many wheelchair users (WU). However, they have also been related to the risk of falling or developing upper limb injuries. Transfer abilities are usually evaluated in clinical settings or biomechanics laboratories, and these methods of assessment are poorly suited to evaluation in real and unconstrained world settings where transfers take place.

Objective

The objective of this paper is to test the feasibility of a system based on a wearable low-cost sensor to monitor transfer skills in real-world settings.

Methods

We collected data from 9 WU wearing triaxial accelerometer on their chest while performing transfers to and from car seats and home furniture. We then extracted significant features from accelerometer data based on biomechanical considerations and previous relevant literature and used machine learning algorithms to evaluate the performance of wheelchair transfers and detect their occurrence from a continuous time series of data.

Results

Results show a good predictive accuracy of support vector machine classifiers when determining the use of head-hip relationship (75.9%) and smoothness of landing (79.6%) when the starting and ending of the transfer are known. Automatic transfer detection reaches performances that are similar to state of the art in this context (multinomial logistic regression accuracy 87.8%). However, we achieve these results using only a single sensor and collecting data in a more ecological manner.

Conclusions

The use of a single chest-placed accelerometer shows good predictive accuracy for algorithms applied independently to both transfer evaluation and monitoring. This points to the opportunity for designing ubiquitous-technology based personalized skill development interventions for WU. However, monitoring transfers still require the use of external inputs or extra sensors to identify the start and end of the transfer, which is needed to perform an accurate evaluation.

Is Fitbit Charge 2 a feasible instrument to monitor daily physical activity and handbike training in persons with spinal cord injury? A pilot study

Study design

It is a longitudinal pilot study.

Objectives

To investigate the feasibility of a low-cost and widely used fitness tracker with step count and heart rate data to monitor daily physical activity in wheelchair users with spinal cord injury (SCI).

Setting

Dutch community.

Methods

Six participants with SCI who were in training for a handbike event were recruited. They were asked to wear a Fitbit Charge 2^® 24 h a day for at least 2 weeks and were questioned about the utility and user-friendliness of this device.

Results

Five out of six participants managed to wear the device nonstop for 2 weeks, and continued to wear the device after this initial period. Most participants were enthusiastic about the direct feedback provided by the tracker and reported the data to be accurate. Data collected during more than 2 months of three participants and during 8 months on one of them showed the possibility of detecting training days and observing interpersonal and intrapersonal variation in daily physical activity level.

Conclusions

A commercially available, low-cost, self-monitoring multi-sensor wrist device or a fitness tracker like the Fitbit Charge 2^® can be a promising instrument to monitor daily activity levels among wheelchair users with SCI. The free commercial dashboard and log data clearly show trends of variations in physical activity and increases in heart rate, which are of value to both researchers and clinicians interested in identifying training schedules of wheelchair athletes.

Effectiveness of a Self-Management Intervention to Promote an Active Lifestyle in Persons With Long-Term Spinal Cord Injury: The HABITS Randomized Clinical Trial

BACKGROUND

Most people with long-term spinal cord injury (SCI) have a very inactive lifestyle. Higher activity levels have been associated with health benefits and enhanced quality of life. Consequently, encouraging an active lifestyle is important and behavioral interventions are needed to establish durable lifestyle changes.

OBJECTIVE

The Healthy Active Behavioral Intervention in SCI (HABITS) study was aimed to evaluate the effectiveness of a structured self-management intervention to promote an active lifestyle in inactive persons with long-term SCI.

METHODS

This assessor-blinded randomized controlled trial was conducted at 4 specialized SCI units in the Netherlands. Sixty-four individuals with long-term SCI (>10 years), wheelchair-user and physically inactive, were included. Participants were randomized to either a 16-week self-management intervention consisting of group meetings and individual counseling and a book, or to a control group that only received information about active lifestyle by one group meeting and a book. Measurements were performed at baseline, 16 weeks, and 42 weeks. Primary outcome measures were self-reported physical activity and minutes per day spent in wheelchair driving. Secondary outcomes included perceived behavioral control (exercise self-efficacy, proactive coping), stages of change concerning exercise, and attitude toward exercise.

RESULTS

Mixed models analyses adjusted for age, sex, level of SCI, time since injury, baseline body mass index, and location did not show significant differences between the intervention and control groups on the primary and secondary outcomes ( P ≥ .05).

CONCLUSIONS

A structured 16-week self-management intervention was not effective to change behavior toward a more active lifestyle and to improve perceived behavioral control, stages of change, and attitude.

Validity of consumer-grade activity monitor to identify manual wheelchair propulsion in standardized activities of daily living

Background

Hypoactive lifestyle contributes to the development of secondary complications and lower quality of life in wheelchair users. There is a need for objective and user-friendly physical activity monitors for wheelchair-dependent individuals in order to increase physical activity through self-monitoring, goal setting, and feedback provision.

Objective

To determine the validity of Activ8 Activity Monitors to 1) distinguish two classes of activities: independent wheelchair propulsion from other non-propulsive wheelchair-related activities 2) distinguish five wheelchair-related classes of activities differing by the movement intensity level: sitting in a wheelchair (hands may be moving but wheelchair remains stationary), maneuvering, and normal, high speed or assisted wheelchair propulsion.

Methods

Sixteen able-bodied individuals performed sixteen various standardized 60s-activities of daily living. Each participant was equipped with a set of two Activ8 Professional Activity Monitors, one at the right forearm and one at the right wheel. Task classification by the Active8 Monitors was validated using video recordings. For the overall agreement, sensitivity and positive predictive value, outcomes above 90% are considered excellent, between 70 and 90% good, and below 70% unsatisfactory.

Results

Division in two classes resulted in overall agreement of 82.1%, sensitivity of 77.7% and positive predictive value of 78.2%. 84.5% of total duration of all tasks was classified identically by Activ8 and based on the video material. Division in five classes resulted in overall agreement of 56.6%, sensitivity of 52.8% and positive predictive value of 51.9%. 59.8% of total duration of all tasks was classified identically by Activ8 and based on the video material.

Conclusions

Activ8 system proved to be suitable for distinguishing between active wheelchair propulsion and other non-propulsive wheelchair-related activities. The ability of the current system and algorithms to distinguish five various wheelchair-related activities is unsatisfactory.

Validity of activity monitors in wheelchair users: A systematic review

Assessing physical activity (PA) in manual wheelchair users (MWUs) is challenging because of their different movement patterns in comparison to the ambulatory population. The aim of this review was to investigate the validity of portable monitors in quantifying PA in MWUs. A systematic literature search was performed. The data source was full reports of validation and evaluation studies in peer-reviewed journals and conference proceedings. Eligible articles between January 1, 1999, and September 18, 2015, were identified in three databases: PubMed, Institute of Electrical and Electronics Engineers, and Scopus. A total of 164 articles (158 from the databases and 6 from the citation/reference tracking) were identified, and 29 met the eligibility criteria. Two investigators independently extracted the characteristics from each selected article following a predetermined protocol and completed seven summary tables describing the study characteristics and key outcomes. In the identified studies, the monitors were used to assess three types of PA measures: energy cost, user movement, and wheelchair movement. The customized algorithms/monitors did not estimate energy cost in MWUs as well as the commercial monitors did in the ambulatory population; however, they showed fair accuracy in measuring both wheelchair and user movements.

Measurement of Physical Activity and Energy Expenditure in Wheelchair Users: Methods, Considerations and Future Directions

Accurately measuring physical activity and energy expenditure in persons with chronic physical disabilities who use wheelchairs is a considerable and ongoing challenge. Quantifying various free-living lifestyle behaviours in this group is at present restricted by our understanding of appropriate measurement tools and analytical techniques. This review provides a detailed evaluation of the currently available measurement tools used to predict physical activity and energy expenditure in persons who use wheelchairs. It also outlines numerous considerations specific to this population and suggests suitable future directions for the field. Of the existing three self-report methods utilised in this population, the 3-day Physical Activity Recall Assessment for People with Spinal Cord Injury (PARA-SCI) telephone interview demonstrates the best reliability and validity. However, the complexity of interview administration and potential for recall bias are notable limitations. Objective measurement tools, which overcome such considerations, have been validated using controlled laboratory protocols. These have consistently demonstrated the arm or wrist as the most suitable anatomical location to wear accelerometers. Yet, more complex data analysis methodologies may be necessary to further improve energy expenditure prediction for more intricate movements or behaviours. Multi-sensor devices that incorporate physiological signals and acceleration have recently been adapted for persons who use wheelchairs. Population specific algorithms offer considerable improvements in energy expenditure prediction accuracy. This review highlights the progress in the field and aims to encourage the wider scientific community to develop innovative solutions to accurately quantify physical activity in this population.

Reliability and validity of daily physical activity measures during inpatient spinal cord injury rehabilitation

Objectives:

To assess the test–retest reliability and convergent validity of daily physical activity measures during inpatient spinal cord injury rehabilitation.

Design:

Observational study.

Setting:

Two inpatient spinal cord injury rehabilitation centres.

Subjects:

Participants (n = 106) were recruited from consecutive admissions to rehabilitation.

Methods:

Physical activity during inpatient spinal cord injury rehabilitation stay was recorded on two days via (1) wrist accelerometer, (2) hip accelerometer if ambulatory, and (3) self-report (Physical Activity Recall Assessment for People with Spinal Cord Injury questionnaire). Spearman’s correlations and Bland–Altman plots were utilized for test–retest reliability. Correlations between physical activity measures and clinical measures (functional independence, hand function, and ambulation) were performed.

Results:

Correlations for physical activity measures between Day 1 and Day 2 were moderate to high (ρ = 0.53–0.89). Bland–Altman plots showed minimal bias and more within-subject differences in more active individuals and wide limits of agreement. None of these three physical activity measures correlated with one another. A moderate correlation was found between wrist accelerometry counts and grip strength (ρ = 0.58) and between step counts and measures of ambulation (ρ = 0.62). Functional independence was related to wrist accelerometry (ρ = 0.70) and step counts (ρ = 0.56), but not with self-report.

Conclusion:

The test–retest reliability and convergent validity of the instrumented measures suggest that wrist and hip accelerometers are appropriate tools for use in research studies of daily physical activity in the spinal cord injury rehabilitation setting but are too variable for individual use.

A study on effects of backrest thickness on the upper arm and trunk muscle load during wheelchair propulsion

[Purpose] The purpose of this study was to investigate the effects of the thickness of a wheelchair backrest provided for support and comfort on upper arm and trunk muscle load during wheelchair propulsion by using accelerometers. [Subjects and Methods] The Fourteen healthy participants were enrolled in this study. The study compared effects of three backrest conditions including no pad, a 3-cm-thick lumbar pad, and a 6-cm-thick lumbar pad. The instruments used for measurement were used two accelerometers. The participants were asked to propel their wheelchairs, which had been equipped with two accelerometers, 30 times. [Results] The intensity of muscle movement with the 3-cm-thick lumbar pad was significantly lower than the intensities with no lumbar pad and the 6-cm-thick lumbar pad. The muscle intensity did not differ significantly between the no pad and 6-cm-thick lumbar pad conditions. [Conclusion] An appropriately thick backrest has good effects on upper arm and trunk muscles during wheelchair propulsion. In the future, we must consider the appropriate backrest thickness for providing wheelchair users with a comfortable wheelchair.