Real-Life Wheelchair Mobility Metrics from IMUs.

Daily wheelchair ambulation is seen as a risk factor for shoulder problems, which are prevalent in manual wheelchair users. To examine the long-term effect of shoulder load from daily wheelchair ambulation on shoulder problems, quantification is required in real-life settings. In this study, we describe and validate a comprehensive and unobtrusive methodology to derive clinically relevant wheelchair mobility metrics (WCMMs) from inertial measurement systems (IMUs) placed on the wheelchair frame and wheel in real-life settings. The set of WCMMs includes distance covered by the wheelchair, linear velocity of the wheelchair, number and duration of pushes, number and magnitude of turns and inclination of the wheelchair when on a slope. Data are collected from ten able-bodied participants, trained in wheelchair-related activities, who followed a 40 min course over the campus. The IMU-derived WCMMs are validated against accepted reference methods such as Smartwheel and video analysis. Intraclass correlation (ICC) is applied to test the reliability of the IMU method. IMU-derived push duration appeared to be less comparable with Smartwheel estimates, as it measures the effect of all energy applied to the wheelchair (including thorax and upper extremity movements), whereas the Smartwheel only measures forces and torques applied by the hand at the rim. All other WCMMs can be reliably estimated from real-life IMU data, with small errors and high ICCs, which opens the way to further examine real-life behavior in wheelchair ambulation with respect to shoulder loading. Moreover, WCMMs can be applied to other applications, including health tracking for individual interest or in therapy settings.

Division, result and score margin alter the physical and technical performance of elite wheelchair tennis players.

This study determined the physical and technical demands of elite wheelchair tennis (WT) match-play, how the demands differed between divisions (Men, Women, Quad) and the effect that set result and score margin had on these demands. Seventeen WT players were monitored during a singles competition. Physical measures of performance were analysed using an indoor tracking system and inertial measurement units. Technical measures of performance were examined using video analysis. Physical measures of performance differed by division (Men > Women > Quad) for most parameters. Rallies were longer during Men's (P = 0.027) and Women's (P = 0.004) matches compared to Quad's and fewer shots were hit off 2 bounces in Men's matches compared to Women's and Quad's (P ≤ 0.026). High-speed activity (HSA) increased during losing sets (P = 0.043). Most physical measures of performance increased by moderate to large effects during sets with a small score margin (≤3 games differential). Mean speed and HSA were similar during losing sets, regardless of margin, but decreased (large effects) when winning by a large margin. This study demonstrated the physical and technical demands that elite WT players need to be prepared for and how situational factors can influence these demands.

Wearable Wheelchair Mobility Performance Measurement in Basketball, Rugby, and Tennis: Lessons for Classification and Training.

Athlete impairment level is an important factor in wheelchair mobility performance (WMP) in sports. Classification systems, aimed to compensate impairment level effects on performance, vary between sports. Improved understanding of resemblances and differences in WMP between sports could aid in optimizing the classification methodology. Furthermore, increased performance insight could be applied in training and wheelchair optimization. The wearable sensor-based wheelchair mobility performance monitor (WMPM) was used to measure WMP of wheelchair basketball, rugby and tennis athletes of (inter-)national level during match-play. As hypothesized, wheelchair basketball athletes show the highest average WMP levels and wheelchair rugby the lowest, whereas wheelchair tennis athletes range in between for most outcomes. Based on WMP profiles, wheelchair basketball requires the highest performance intensity, whereas in wheelchair tennis, maneuverability is the key performance factor. In wheelchair rugby, WMP levels show the highest variation comparable to the high variation in athletes' impairment levels. These insights could be used to direct classification and training guidelines, with more emphasis on intensity for wheelchair basketball, focus on maneuverability for wheelchair tennis and impairment-level based training programs for wheelchair rugby. Wearable technology use seems a prerequisite for further development of wheelchair sports, on the sports level (classification) and on individual level (training and wheelchair configuration).

Improving Mobility Performance in Wheelchair Basketball.

OBJECTIVE: This study aimed to investigate which characteristics of athlete, wheelchair and athlete-wheelchair interface are the best predictors of wheelchair basketball mobility performance. DESIGN: A total of 60 experienced wheelchair basketball players performed a wheelchair mobility performance test to assess their mobility performance. To determine which variables were the best predictors of mobility performance, forward stepwise linear regression analyses were performed on a set of 33 characteristics, including 10 athlete, 19 wheelchair, and 4 athlete-wheelchair interface characteristics. RESULTS: A total of 8 of the characteristics turned out to be significant predictors of wheelchair basketball mobility performance. Classification, experience, maximal isometric force, wheel axis height, and hand rim diameter-which both are interchangeable with each other and wheel diameter-camber angle, and the vertical distance between shoulder and rear wheel axis-which was interchangeable with seat height-were positively associated with mobility performance. The vertical distance between the front seat and the footrest was negatively associated with mobility performance. CONCLUSION: With this insight, coaches and biomechanical specialists are provided with statistical findings to determine which characteristics they could focus on best to improve mobility performance. Six out of 8 predictors are modifiable and can be optimized to improve mobility performance. These adjustments could be carried out both in training (maximal isometric force) and in wheelchair configurations (eg, camber angle).

Development, construct validity and test-retest reliability of a field-based wheelchair mobility performance test for wheelchair basketball.

The aim of this study was to develop and describe a wheelchair mobility performance test in wheelchair basketball and to assess its construct validity and reliability. To mimic mobility performance of wheelchair basketball matches in a standardised manner, a test was designed based on observation of wheelchair basketball matches and expert judgement. Forty-six players performed the test to determine its validity and 23 players performed the test twice for reliability. Independent-samples t-tests were used to assess whether the times needed to complete the test were different for classifications, playing standards and sex. Intraclass correlation coefficients (ICC) were calculated to quantify reliability of performance times. Males performed better than females (P < 0.001, effect size [ES] = -1.26) and international men performed better than national men (P < 0.001, ES = -1.62). Performance time of low (≤2.5) and high (≥3.0) classification players was borderline not significant with a moderate ES (P = 0.06, ES = 0.58). The reliability was excellent for overall performance time (ICC = 0.95). These results show that the test can be used as a standardised mobility performance test to validly and reliably assess the capacity in mobility performance of elite wheelchair basketball athletes. Furthermore, the described methodology of development is recommended for use in other sports to develop sport-specific tests.

The Physical Demands of Wheelchair Tennis Match Play: A Systematic Review with Meta-analysis.

BACKGROUND: Wheelchair tennis, a globally popular sport, features a professional tour spanning 40 countries and over 160 tournaments. Despite its widespread appeal, information about the physical demands of wheelchair tennis is scattered across various studies, necessitating a comprehensive systematic review to synthesise available data. OBJECTIVE: The aim was to provide a detailed synthesis of the physical demands associated with wheelchair tennis, encompassing diverse factors such as court surfaces, performance levels, sport classes, and sexes. METHODS: We conducted comprehensive searches in the PubMed, Embase, CINAHL, and SPORTDiscus databases, covering articles from inception to March 1, 2023. Forward and backward citation tracking from the included articles was carried out using Scopus, and we established eligibility criteria following the Population, Exposure, Comparison, Outcome, and Study design (PECOS) framework. Our study focused on wheelchair tennis players participating at regional, national, or international levels, including both juniors and adults, and open and quad players. We analysed singles and doubles matches and considered sex (male, female), sport class (open, quad), and court surface type (hard, clay, grass) as key comparative points. The outcomes of interest encompassed play duration, on-court movement, stroke performance, and physiological match variables. The selected study designs included observational cross-sectional, longitudinal, and intervention studies (baseline data only). We calculated pooled means or mean differences with 95% confidence intervals (CIs) and employed a random-effects meta-analysis with robust variance estimation. We assessed heterogeneity using Cochrane Q and 95% prediction intervals. RESULTS: Our literature search retrieved 643 records, with 24 articles meeting our inclusion criteria. Most available information focused on international male wheelchair tennis players in the open division, primarily competing in singles on hard courts. Key findings (mean [95% CI]) for these players on hard courts were match duration 65.9 min [55.0-78.8], set duration 35.0 min [28.2-43.5], game duration 4.6 min [0.92-23.3], rally duration 6.1 s [3.7-10.2], effective playing time 19.8% [18.9-20.7], and work-to-rest ratio 1:4.1 [1:3.7-1:4.4]. Insufficient data were available to analyse play duration for female players. However, for the available data on hard court matches, the average set duration was 34.8 min [32.5-37.2]. International male players on hard court covered an average distance per match of 3859 m [1917-7768], with mean and peak average forward speeds of 1.06 m/s [0.85-1.32] and 3.55 m/s [2.92-4.31], respectively. These players executed an average of 365.9 [317.2-422.1] strokes per match, 200.6 [134.7-299.0] per set, 25.4 [16.7-38.7] per game, and 3.4 [2.6-4.6] per rally. Insufficient data were available for a meta-analysis of female players' on-court movement and stroke performance. The average and peak heart rates of international male players on hard court were 134.3 [124.2-145.1] and 166.0 [132.7-207.6] beats per minute, and the average match heart rate expressed as a percentage of peak heart rate was 74.7% [46.4-100]. We found no studies concerning regional players or juniors, and only one study on doubles match play. CONCLUSIONS: While we present a comprehensive overview of the physical demands of wheelchair tennis, our understanding predominantly centres around international male players competing on hard courts in the open division. To attain a more comprehensive insight into the sport's physical requirements, future research should prioritise the inclusion of data on female and quad players, juniors, doubles, and matches played on clay and grass court surfaces. Such endeavours will facilitate the development of more tailored and effective training programmes for wheelchair tennis players and coaches. The protocol for this systematic review was registered a priori at the International Platform of Registered Systematic Review and Meta-analysis Protocols (Registration https://doi.org/10.37766/inplasy2023.3.0060 ).

Load and performance monitoring in wheelchair court sports: A narrative review of the use of technology and practical recommendations.

Quantifying measures of physical loading has been an essential part of performance monitoring within elite able-bodied sport, facilitated through advancing innovative technology. In wheelchair court sports (WCS) the inter-individual variability of physical impairments in the athletes increases the necessity for accurate load and performance measurements, while at the same time standard load monitoring methods (e.g. heart-rate) often fail in this group and dedicated WCS performance measurement methods are scarce. The objective of this review was to provide practitioners and researchers with an overview and recommendations to underpin the selection of suitable technologies for a variety of load and performance monitoring purposes specific to WCS. This review explored the different technologies that have been used for load and performance monitoring in WCS. During structured field testing, magnetic switch-based devices, optical encoders and laser systems have all been used to monitor linear aspects of performance. However, movement in WCS is multidirectional, hence accelerations, decelerations and rotational performance and their impact on physiological responses and determination of skill level, is also of interest. Subsequently both for structured field testing as well as match-play and training, inertial measurement units mounted on wheels and frame have emerged as an accurate and practical option for quantifying linear and non-linear movements. In conclusion, each method has its place in load and performance measurement, yet inertial sensors seem most versatile and accurate. However, to add context to load and performance metrics, position-based acquisition devices such as automated image-based processing or local positioning systems are required.Highlights Objective measures of wheelchair mobility performance are paramount in wheelchair court sport support, since they enable quantification of workload across athletes of all classifications and in structured field testing, training and match play settings.Given the variety of methods for load and performance monitoring in wheelchair court sports, this review: identified and examined the technology available; provides meaningful insights and decision guidelines; describes applicability for different goals; and proposes practical recommendations for researchers and sports professionals.Wheelchair mounted inertial sensors are most reliable and versatile for measuring wheelchair mobility performance and estimates of workload, yet a combination with local position measurement via indoor tracking or image-based processing could be useful to add context.For wheelchair athletes bound to a wheelchair for daily use, workload monitoring on a regular basis, both on- and off-court, is crucial to avoid overuse injuries. Alternatively, in athletes with lower severity impairments often lack frequent exposure to optimal and progressive loading, reducing the likelihood of positive physiological adaptations.

Obtaining wheelchair kinematics with one sensor only? The trade-off between number of inertial sensors and accuracy for measuring wheelchair mobility performance in sports.

In wheelchair sports, the use of Inertial Measurement Units (IMUs) has proven to be one of the most accessible ways for ambulatory measurement of wheelchair kinematics. A three-IMU configuration, with one IMU attached to the wheelchair frame and two IMUs on each wheel axle, has previously shown accurate results and is considered optimal for accuracy. Configurations with fewer sensors reduce costs and could enhance usability, but may be less accurate. The aim of this study was to quantify the decline in accuracy for measuring wheelchair kinematics with a stepwise sensor reduction. Ten differently skilled participants performed a series of wheelchair sport specific tests while their performance was simultaneously measured with IMUs and an optical motion capture system which served as reference. Subsequently, both a one-IMU and a two-IMU configuration were validated and the accuracy of the two approaches was compared for linear and angular wheelchair velocity. Results revealed that the one-IMU approach show a mean absolute error (MAE) of 0.10 m/s for absolute linear velocity and a MAE of 8.1°/s for wheelchair angular velocity when compared with the reference system. The two-IMU approach showed similar differences for absolute linear wheelchair velocity (MAE 0.10 m/s), and smaller differences for angular velocity (MAE 3.0°/s). Overall, a lower number of IMUs used in the configuration resulted in a lower accuracy of wheelchair kinematics. Based on the results of this study, choices regarding the number of IMUs can be made depending on the aim, required accuracy and resources available.

Wheelchair mobility performance of elite wheelchair tennis players during four field tests: Inter-trial reliability and construct validity.

The purpose of the current study was to assess the inter-trial reliability and construct validity (talented juniors vs. international adult players) of four wheelchair tennis field tests using inertial measurement units (IMUs). Twenty-one elite wheelchair tennis players completed four tests, which evaluate the sprinting and manoeuvrability abilities in wheelchair tennis. During all tests 3 IMUs were attached to both wheels and the frame of the athlete's wheelchair. The IMUs enabled analysis of individual test dynamic characteristics, i.e. the linear/rotational velocity and acceleration data, as well as detected pushes. All tests showed high ICCs (0.95-0.99) for the inter-trial reliability for the IMU-based end times and also the construct validity was good, i.e. talented juniors could be discriminated from international adults. Also, velocities and accelerations during the tests could be consistently visualized, meaning that differences in test performance among participants could be designated. Within the experimental context, the field tests could be regarded as reliable and valid. With the use of IMUs it is possible to verify more detailed performance characteristics, visualize the test execution, as well as differentiate between a talented junior and international adult group and within individuals over time.

The Effect of Small-Sided Game Formats on Physical and Technical Performance in Wheelchair Basketball.

PURPOSE: To examine the effects of different small-sided games (SSGs) on physical and technical aspects of performance in wheelchair basketball (WB) players. DESIGN: Observational cohort study. METHODS: Fifteen highly trained WB players participated in a single 5v5 (24-s shot clock) match and three 3v3 SSGs (18-s shot clock) on a (1) full court, (2) half-court, and (3) modified-length court. During all formats, players' activity profiles were monitored using an indoor tracking system and inertial measurement units. Physiological responses were monitored via heart rate and rating of perceived exertion. Technical performance, that is, ball handling, was monitored using video analysis. Repeated-measures analysis of variance and effect sizes (ESs) were calculated to determine the statistical significance and magnitude of any differences between game formats. RESULTS: Players covered less distance and reached lower peak speeds during half-court (P ≤ .0005; ES ≥ very large) compared with all other formats. Greater distances were covered, and more time was spent performing moderate- and high-speed activity (P ≤ .008; ES ≥ moderate) during full court compared with all other formats. Game format had little bearing on physiological responses, and the only differences in technical performance observed were in relation to 5v5. Players spent more time in possession, took more shots, and performed more rebounds in all 3v3 formats compared with 5v5 (P ≤ .028; ES ≥ moderate). CONCLUSIONS: Court dimensions affect the activity profiles of WB players during 3v3 SSGs yet had little bearing on technical performance when time pressures (shot clocks) were constant. These findings have important implications for coaches to understand which SSG format may be most suitable for physically and technically preparing WB players.

Wheelchair Mobility Performance Enhancement by Changing Wheelchair Properties: What Is the Effect of Grip, Seat Height, and Mass?

PURPOSE: To provide insight on the effect of wheelchair settings on wheelchair mobility performance (WMP). METHODS: Twenty elite wheelchair basketball athletes of low (n = 10) and high classification (n = 10) were tested in a wheelchair-basketball-directed field test. Athletes performed the test in their own wheelchairs, which were modified for 5 additional conditions regarding seat height (high-low), mass (central-distributed), and grip. The previously developed inertial-sensor-based WMP monitor was used to extract wheelchair kinematics in all conditions. RESULTS: Adding mass showed most effect on WMP, with a reduced average acceleration across all activities. Once distributed, additional mass also reduced maximal rotational speed and rotational acceleration. Elevating seat height had an effect on several performance aspects in sprinting and turning, whereas lowering seat height influenced performance minimally. Increased rim grip did not alter performance. No differences in response were evident between low- and high-classified athletes. CONCLUSIONS: The WMP monitor showed sensitivity to detect performance differences due to the small changes in wheelchair configuration. Distributed additional mass had the most effect on WMP, whereas additional grip had the least effect of conditions tested. Performance effects appear similar for both low- and high-classified athletes. Athletes, coaches, and wheelchair experts are provided with insight into the performance effect of key wheelchair settings, and they are offered a proven sensitive method to apply in sport practice, in their search for the best wheelchair-athlete combination.

The Future of Classification in Wheelchair Sports: Can Data Science and Technological Advancement Offer an Alternative Point of View?

PURPOSE: Classification is a defining factor for competition in wheelchair sports, but it is a delicate and time-consuming process with often questionable validity. New inertial sensor-based measurement methods applied in match play and field tests allow for more precise and objective estimates of the impairment effect on wheelchair-mobility performance. The aim of the present research was to evaluate whether these measures could offer an alternative point of view for classification. METHODS: Six standard wheelchair-mobility performance outcomes of different classification groups were measured in match play (n = 29), as well as best possible performance in a field test (n = 47). RESULTS: In match results, a clear relationship between classification and performance level is shown, with increased performance outcomes in each adjacent higher-classification group. Three outcomes differed significantly between the low- and mid-classified groups, and 1, between the mid- and high-classified groups. In best performance (field test), there was a split between the low- and mid-classified groups (5 out of 6 outcomes differed significantly) but hardly any difference between the mid- and high-classified groups. This observed split was confirmed by cluster analysis, revealing the existence of only 2 performance-based clusters. CONCLUSIONS: The use of inertial sensor technology to obtain objective measures of wheelchair-mobility performance, combined with a standardized field test, produced alternative views for evidence-based classification. The results of this approach provide arguments for a reduced number of classes in wheelchair basketball. Future use of inertial sensors in match play and field testing could enhance evaluation of classification guidelines, as well as individual athlete performance.

Self-reported physical functioning was more influenced by pain than performance-based physical functioning in knee-osteoarthritis patients.

BACKGROUND AND OBJECTIVES: To test the hypothesis that self-reported physical functioning is more influenced by pain than performance-based physical functioning. METHODS: 163 knee-osteoarthritis patients completed the performance-based DynaPort KneeTest (DPKT), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and SF-36 (self-report measures of pain and physical functioning) before, 3, 6, and 12 months after knee replacement. RESULTS: Correlations between (two) self-reported measures of functioning and (two) pain measures were higher (0.57-0.74) than correlations between the performance-based measure of functioning and the two pain measures (0.20 and 0.26). In factor analysis, WOMAC and SF-36 pain and physical functioning subscores loaded on the first factor (eigenvalue 3.2), while DPKT KneeScore2 loaded on the second factor (eigenvalue 0.92). Before surgery, correlations between performance-based and self-reported physical functioning were higher in patients with less pain (0.43) compared to patients with more pain (0.17), for the WOMAC (as expected), but not for the SF-36. After surgery, when the pain had diminished, the correlations between performance-based and self-reported physical functioning were higher, especially for the WOMAC. CONCLUSIONS: Our hypothesis was convincingly supported by the results of the WOMAC, and somewhat less by the results of the SF-36. We consider this as evidence for a lack of content validity of the WOMAC.

The accuracy of measuring the kinematics of rising from a chair with accelerometers and gyroscopes.

The purpose of this study was to assess the accuracy of measuring angle and angular velocity of the upper body and upper leg during rising from a chair with accelerometers, using low-pass filtering of the accelerometer signal. Also, the improvement in accuracy of the measurement with additional use of high-pass filtered gyroscopes was assessed. Two uni-axial accelerometers and one gyroscope (DynaPort) per segment were used to measure angles and angular velocities of upper body and upper leg. Calculated angles and angular velocities were compared to a high-quality optical motion analysis system (Optotrak), using root mean squared error (RMS) and correlation coefficient (r) as parameters. The results for the sensors showed that two uni-axial accelerometers give a reasonable accurate measurement of the kinematics of rising from a chair (RMS = 2.9, 3.5, and 2.6 degrees for angle and RMS = 9.4, 18.4, and 11.5 degrees /s for angular velocity for thorax, pelvis, and upper leg, respectively). Additional use of gyroscopes improved the accuracy significantly (RMS = 0.8, 1.1, and 1.7 degrees for angle and RMS = 2.6, 4.0 and 4.9 degrees /s for angular velocity for thorax, pelvis and upper leg, respectively). The low-pass Butterworth filter had optimal cut-off frequencies of 1.05, 1.3, and 1.05 for thorax, pelvis, and upper leg, respectively. For the combined signal, the optimal cut-off frequencies were 0.18, 0.2, and 0,38 for thorax, pelvis and upper leg, respectively. The filters showed no subject specificity. This study provides an accurate, inexpensive and simple method to measure the kinematics of movements similar to rising from a chair.

Reproducibility and validity of the DynaPort KneeTest.

OBJECTIVE: To determine the reproducibility and validity of the DynaPort KneeTest, a performance-based test that measures quality of movement of patients undergoing total knee replacement (TKR). METHODS: A total of 92 patients with osteoarthritis (OA) of the knee performed the KneeTest twice on the same day; 94 healthy controls performed the KneeTest once. During the test, 29 activities were performed with accelerometers attached to the body. Relevant functional parameters were extracted from the accelerometers. A selection of parameters was used to calculate activity scores, based on the ability of parameters to discriminate between patients and controls (regression analyses). Based on internal consistency analyses (Cronbach's alpha), redundant activities were removed. Four cluster scores and a total KneeScore were calculated from the remaining activity scores. Reproducibility and validity of the cluster scores and the total KneeScore 2 were assessed. RESULTS: Based on internal consistency analyses, the test was reduced to 23 activities. Inter- and intraobserver reliability using intraclass correlation coefficients were 0.90 (0.83-0.94) and 0.95 (0.83-0.98), respectively. Limits of inter- and intraobserver agreement were -8.3 to 11.3 and -4.2 to 9.0. Construct validity was confirmed by expected correlations with the Western Ontario and McMaster University Osteoarthritis Index physical functioning (0.55), Medical Outcomes Study Short Form-36 Health Survey physical functioning (0.62), and Knee Society Score function (0.64). CONCLUSION: The KneeTest is a useful performance-based measure for research in patients with knee OA undergoing TKR, with good reliability and validity. Further research is required to improve its usefulness for clinical practice.