The impact of trunk impairment on performance-determining activities in wheelchair rugby

The impact of Wheelchair Rugby classification lineup structure on possession outcome

OBJECTIVES

To investigate the impact that the structure and combination of athlete classification within lineups has on possession outcome in Wheelchair Rugby (WR).

DESIGN

Retrospective.

METHODS

Analysis was conducted using data from all 18 WR matches from the 2020 Tokyo Paralympic Games. Pearson's chi-squared analysis was conducted to investigate the effect of lineup structures on performance and a nested generalised logistic mixed model (GLMM) was fitted to the data to investigate the association between independent variables and the outcome of possessions. Specifically, the impact of offensive and defensive lineup structures on possession outcome and whether the offensive and defensive lineup structures matching or not impact possession outcome.

RESULTS

There was a significant relationship between the offensive lineup structure and possession outcome. Balanced lineups had greater turnovers than expected. Balanced lineups also had fewer tries than expected, whilst high-low lineups had fewer than expected turnovers. There were no significant associations between the defensive lineup structure and possession outcome. Furthermore, no significant associations were found between whether the structure of the offensive and defensive lineup matched (or not) and the possession outcome.

CONCLUSIONS

The findings suggest that the offensive team's lineup structure plays a more prominent role in impacting possession outcome, compared to the defensive team's lineup structure. The present results provide valuable insights into WR performance for coaches, practitioners, and researchers.

Cluster analysis of multiple impairment measures in evidence-based classification for para-alpine sit skiers

The International Paralympic Committee has been promoting the development of evidence-based classification to reduce the subjectivity in current decision-making systems. The current study aimed to evaluate the validity of the impairment and performance tests for para-alpine sit skiing classification, and whether cluster analysis of the measures would produce a valid classification structure. Thirty-eight para-alpine sit skiers with different disabilities completed seven tests. During these tests, isometric trunk strength, trunk muscle excitation, trunk range of movement (ROM), and simulated skiing performance (board tilt angle) were assessed. Correlations between the measures and the board tilt angle were calculated. To group athletes, K-means cluster analysis was performed according to how much the impairment measures affected the board tilting. There were significant correlations between all measures and the maximal board tilt angle (r = 0.35-0.81, p < 0.05). The cluster analysis revealed that the introduction of ROM and muscle excitation was an effective supplement to strength measures in improving the classification accuracy (53%-79%). It produced four clusters with strong structures (mean silhouette coefficient = 0.81) and large and significant inter-cluster differences in most measures and performance between clusters (p < 0.05). The cluster analysis produced classes comprising athletes with similar degrees of activity limitation. All tests reported can help establish a more transparent classification system for para-alpine sit skiers. This study also provides a reference for evidence-based classification systems in other Para sports.

Home-based arm cycling exercise improves trunk control in persons with incomplete spinal cord injury: an observational study

Arm cycling is used for cardiorespiratory rehabilitation but its therapeutic effects on the neural control of the trunk after spinal cord injury (SCI) remain unclear. We investigated the effects of single session of arm cycling on corticospinal excitability, and the feasibility of home-based arm cycling exercise training on volitional control of the erector spinae (ES) in individuals with incomplete SCI. Using transcranial magnetic stimulation, we assessed motor evoked potentials (MEPs) in the ES before and after 30 min of arm cycling in 15 individuals with SCI and 15 able-bodied controls (Experiment 1). Both groups showed increased ES MEP size after the arm cycling. The participants with SCI subsequently underwent a 6-week home-based arm cycling exercise training (Experiment 2). MEP amplitudes and activity of the ES, and movements of the trunk during reaching, self-initiated rapid shoulder flexion, and predicted external perturbation tasks were measured. After the training, individuals with SCI reached further and improved trajectory of the trunk during the rapid shoulder flexion task, accompanied by increased ES activity and MEP amplitudes. Exercise adherence was excellent. We demonstrate preserved corticospinal drive after a single arm cycling session and the effects of home-based arm cycling exercise training on trunk function in individuals with SCI.

Utilizing spinal cord injury stratification during classification for allocation of para surfing sport classes

OBJECTIVES

The purpose of this study was to determine which stratification (anatomical versus functional) forms a better construct for classification of para surfers with spinal cord injury; to assess the groupings of these para surfers; and to evaluate the strength of association between manual muscle testing and surfing performance.

DESIGN

Cross-sectional.

METHODS

Archived data from classification records including demographics, spinal cord injury levels, trunk strength, and limb strength were compared to judged wave scores and competition rankings.

RESULTS

Participants (n = 70, male n = 56; female n = 14) met inclusion criteria and were classified into Para Surfing Kneeling (n = 9); Sit (n = 11); Prone 1 (n = 25); and Prone 2 (n = 25) sport classes. Reliability statistics showed that functional grouping (Cronbach's α = 0.759) is better grouped with strength testing and rankings compared to anatomical grouping (Cronbach's α = 0.721). Under exploratory factor analysis with 2 fixed components, based on the factor loadings (rank and strength) functional stratification (0.978) is better aligned compared to anatomical stratification (0.785) for grouping of surfers. Further, the association and impact of strength with functional spinal cord level stratification were confirmed using regression analysis (chi-square of 74.06 with p-value <.0001).

CONCLUSIONS

Trunk and limb strengths have been shown to influence wave riding performance in surfers with spinal cord injury. Surfers with spinal cord injury can equitably be classified into one of the four para surfing sport classes. The use of functional stratification of spinal cord injury with trunk and limb strengths should be considered as an integral component in para surfing athlete sport classification.

Wheelchair rugby players maintain sprint performance but alter propulsion biomechanics after simulated match play

The study aimed to explore the influence of a sports-specific intermittent sprint protocol (ISP) on wheelchair sprint performance and the kinetics and kinematics of sprinting in elite wheelchair rugby (WR) players with and without spinal cord injury (SCI). Fifteen international WR players (age 30.3 ± 5.5 years) performed two 10-s sprints on a dual roller wheelchair ergometer before and immediately after an ISP consisting of four 16-min quarters. Physiological measurements (heart rate, blood lactate concentration, and rating of perceived exertion) were collected. Three-dimensional thorax and bilateral glenohumeral kinematics were quantified. Following the ISP, all physiological parameters significantly increased (p ≤ 0.027), but neither sprinting peak velocity nor distance traveled changed. Players propelled with significantly reduced thorax flexion and peak glenohumeral abduction during both the acceleration (both -5°) and maximal velocity phases (-6° and 8°, respectively) of sprinting post-ISP. Moreover, players exhibited significantly larger mean contact angles (+24°), contact angle asymmetries (+4%), and glenohumeral flexion asymmetries (+10%) during the acceleration phase of sprinting post-ISP. Players displayed greater glenohumeral abduction range of motion (+17°) and asymmetries (+20%) during the maximal velocity phase of sprinting post-ISP. Players with SCI (SCI, n = 7) significantly increased asymmetries in peak power (+6%) and glenohumeral abduction (+15%) during the acceleration phase post-ISP. Our data indicates that despite inducing physiological fatigue resulting from WR match play, players can maintain sprint performance by modifying how they propel their wheelchair. Increased asymmetry post-ISP was notable, which may be specific to impairment type and warrants further investigation.

Reliability of anaerobic and aerobic mobility performance tests used in wheelchair rugby, wheelchair basketball and wheelchair tennis: A systematic review

BACKGROUND

Understanding the reliability and validity of field-based mobility and performance tests used within the wheelchair sports of basketball (WCB), rugby (WCR) and tennis (WCT) can assist in understanding an athletes' physiological state, training effects, and/or assist with optimising their wheelchair-user interface.

PURPOSE

To examine, evaluate and synthesize current aerobic and anaerobic field-based mobility and performance tests used in WCB, WCR and WCT.

METHODS

A systematic search was performed according to PRISMA guidelines. Studies were included if they investigated performance tests in WCB, WCR and WCT and reported reliability.

RESULTS

Twenty-one studies covering 45 mobility/performance tests were included (anaerobic, n = 35; aerobic, n = 10), with agility and repeated sprints (n = 13) being the most common, followed by linear-sprints (n = 11). Repeated sprint ability (n = 2) and submaximal field-tests (n = 2) were the least frequent. Intra-class correlations among all tests ranged from 0.62 to 0.99, with agility and repeated sprints being 0.65-0.98, followed by values of 0.62-0.99 for linear-sprint, 0.96-0.99 for repeated sprints and 0.85-0.97 for submaximal field-tests.

CONCLUSION

The most frequently measured performance tests were anaerobic tests focusing on agility and repeated sprints. Given the low number of aerobic tests in WCB, WCR and WCT, future research should focus on reliable and valid ways to measure and track performance.

Development of Tests for Arm Coordination Impairment in Paralympic Classification

Background

In Paralympic sport, classification of impairment with the ability to detect misrepresentation of abilities is mandatory. In wheelchair rugby, there is currently no objective method to classify arm coordination impairment. In previous research, sufficient correlation between the spiral test (ST) and activity in wheelchair rugby was found in athletes with coordination impairment. However, the ST depends on maximum voluntary effort.

Purpose

To assess if the ST is an objective test for arm coordination impairment, in which maximum voluntary effort can be distinguished from intentional misrepresentation. The aims of this study were to (1) assess the test-retest reliability of the ST and (2) assess if Fitts's law is applicable to the ST.

Methods

Nineteen volunteers without impairments performed two sessions with three STs per arm. The STs were projected and measured on a tablet and had three different indices of difficulty based on differences in spiral width. The time to complete the spiral was measured and a penalty time was added for each time the borderline of the spiral was touched (3 s) or crossed (5 s).

Results

Test-retest reliability was assessed using a Bland-Altman analysis and showed limits of agreement that were wider than the margins of 2SD from the group mean. Repeated measurement correlation coefficients between the index of difficulty according to Fitts's law and the movement time were > 0.95 (p-value < 0.001) for both test and retest. A post-hoc optimisation of penalty times revealed an optimum penalty time of 2.0 s for the dominant arm and 2.5 for the non-dominant arm for any contact with the margins of the spiral.

Conclusions

The ST has sufficient test-retest reliability and Fitts's law is applicable. Therefore, it is a promising option for classification of arm coordination impairment with the option to distinguish intentional misrepresentation from maximum voluntary effort.

Effects of trunk muscle activation on trunk stability, arm power, blood pressure and performance in wheelchair rugby players with a spinal cord injury

Objective: In wheelchair rugby (WR) athletes with tetraplegia, wheelchair performance may be impaired due to (partial) loss of innervation of upper extremity and trunk muscles, and low blood pressure (BP). The objective was to assess the effects of electrical stimulation (ES)-induced co-contraction of trunk muscles on trunk stability, arm force/power, BP, and WR performance.Design: Cross-sectional study.Setting: Rehabilitation research laboratory and WR court.Participants: Eleven WR athletes with tetraplegia.Interventions: ES was applied to the rectus abdominis, obliquus externus abdominis and erector spinae muscles. For every test, the ES condition was compared to the non-ES condition.Outcome measures: Stability was assessed with reaching tasks, arm force/power with an isokinetic test on a dynamometer, BP during an ES protocol and WR skill performance with the USA Wheelchair Rugby Skill Assessment.Results: Overall reaching distance (ES 14.6 ± 7.5 cm, non-ES 13.4 ± 8.2 cm), and BP showed a significant increase with ES. Arm force (ES 154 ± 106 N, non-ES 148 ± 102 N) and power (ES 37 ± 26 W, non-ES 36 ± 25 W), and WR skills were not significantly improved.Conclusion: ES-induced trunk muscle activation positively affects trunk stability and BP, but not arm force/power. No effects were found in WR skill performance, probably due to abdominal strapping. More research is needed to assess different ES (training) protocols and longitudinal effects.

Evidence-Based Classification in Powerchair Football: Determining the Determinants

The purpose of this study was to initiate the development of an evidence-based sport classification system for powerchair football, a sport that serves athletes with physical impairments. Sport classification is designed to increase participation by minimizing the impact of impairment on competition outcome, and powerchair football lacks an evidence-based system of classification which is required of Paralympic sports. A number of approaches were used to build the theoretical model of sport performance (Step 2 of the International Paralympic Committee model). Key sport activities were identified through surveys of stakeholders and underlying determinants of those key activities were identified through game and database analyses. Current findings support drive control, ball control, communication, and adjustment to the ball as key activities in powerchair football with joint-specific strength and range of motion, sensory, and neurological variables identified as underlying determinants.

Objective Measurement of Ball-Handling Proficiency in Wheelchair Sports: A Systematic Review

Background

In Paralympic sports, classification of athletes based on the impact of impairments on the ability to perform is needed, to prevent a one-sided and predictable outcome of the competition in which the least impaired athlete has the best chance to win. Classification is developing from expert opinion based to evidence based. In wheelchair court sports, there is evidence to support the impact of impairment on wheeled mobility, but not on ball handling. To assess the impact of impairment on the ability to perform ball-handling activities, standardised tests for ball handling are needed.

Purpose

To assess if reliable and valid standardised tests for the measurement of ball-handling proficiency in a wheelchair or able-bodied court sports exist; to assist in the development of Evidence-Based Classification (EBC) in wheelchair court sports according to the guidelines of the International Paralympic Committee (IPC).

Methods

The review was conducted according to the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) statement. Search terms used were “wheelchair,” “ball,” “ball sports,” “test,” and “performance.” Databases searched were Medline, Embase, PubMed, and Sport Discus. Study quality was assessed using the Strengthening the Reporting of Observational Studies in Epidemiology checklist.

Results

Twenty-two articles were included. Foundational Movement Skills in ball-handling proficiency were assessed. Tests for throwing maximal distance showed sufficient reliability and validity. Precision in throwing showed low-to-moderate reliability and conflicting results in validity. Throwing techniques differed between studies. Dribbling the ball showed high reliability, but conflicting results in validity.

Conclusions

Tests for throwing maximal distance, throwing precision, and dribbling the ball can be used in standardised tests for activity limitation in wheelchair court sports. However, tests need to be adapted and standardised and then reassessed for reliability and validity in athletes with and without arm impairment.

Development of evidence-based classification for para surfers with physical impairments: A narrative review

The sport of competitive para surfing is growing internationally without established classification procedures. A classification structure is essential for equitable sport competition and worldwide sport progression. This narrative review summarizes the existing knowledge on Paralympic classification and surfing biomechanics. Its primary purpose is to describe the development of an evidence-based para surfing classification structure that follows the International Paralympic Committee (IPC) Classification Code. Two databases-PubMed and Google Scholar-were searched for three themes: "Paralympic classification", "performance determining factors in surfing", and "impact of impairments on surf performance". The IPC Classification Code and IPC regulations were obtained from the IPC website and official publications. Seventy-six relevant articles were utilized to guide the design of this preliminary para surfing classification structure. A conceptual framework on athlete characteristics, adaptive sport characteristics, and use of equipment is presented to build the essential knowledge base for continual growth of para surfing. This classification structure and conceptual framework will support para surfing sport expansion and help pave the way for its inclusion in the Paralympic Games.

A Role for Trunk Function in Elite Recumbent Handcycling Performance?

Handcycling classification considers trunk function, but there is limited scientific evidence of trunk involvement in recumbent performance. This study investigated the association between trunk function and recumbent handcycling performance of athletes without upper-limb impairments (H3-H4 sport classes). The study was divided into two parts. First, 528 time-trial results from 81 handcyclists with spinal cord injury (SCI) were obtained between 2014 and 2020. Average time-trial velocity was used as performance measure and SCI level as trunk function determinant. Multilevel regression analysis was performed to analyse differences in performance among SCI groups while correcting for lesion completeness, sex, and age. Second, in 26 handcyclists, standardised trunk flexion strength was measured with a handheld dynamometer. Peak and mean power-output from a sprint test and time-trial average velocity were used as performance measures. Spearman correlations were conducted to investigate the association between trunk strength and performance. Results showed that the different SCI groups did not exhibit significant differences in performance. Furthermore, trunk flexion strength and performance exhibited non-significant weak to moderate correlations (for time-trial speed: rs = 0.36; p = 0.07). Results of both analyses suggest that trunk flexion strength does not seem to significantly impact recumbent handcycling performance in athletes without upper-limb impairments.

Validation of new measures of arm coordination impairment in Wheelchair Rugby

This study aims were twofold: (1) to evaluate the construct validity of the Repetitive Movement Test (RMT) a novel test developed for Wheelchair Rugby classification which evaluates arm coordination impairment at five joints - shoulder, elbow, forearm, wrist and fingers - and (2), pending sufficiently positive results, propose objective minimum impairment criteria (MIC). Forty-two WR athletes with an eligible coordination impairment, and 20 volunteers without impairment completed the RMT and two clinically established coordination tests: the finger-nose test (FNT) and the spiral test (ST). Coordination deduction (CD), an ordinal observational coordination scale, currently used in WR classification, was obtained. Spearman-rank correlation coefficients (SCC) between RMT and ST (0.40 to 0.67) and between RMT and CD (0.31 to 0.53) generally supported RMT construct validity, SCC between RMT and FNT were lower (0.12-0.31). When the scores on ST, FNT and RMT from the sample of WR players were compared with the scores from volunteers without impairment, 93.5% to 100% of WR players had scores > 2SD below the mean of volunteers without impairment on the same test. In conclusion, RMT at the elbow, forearm, wrist and fingers have sufficient construct validity for use in WR. MIC were recommended with ST and RMT.

Optimising classification of proximal arm strength impairment in wheelchair rugby: A proof of concept study

This study examined the relationship between proximal arm strength and mobility performance in wheelchair rugby (WR) athletes and examined whether a valid structure for classifying proximal arm strength impairment could be determined. Fifty-seven trained WR athletes with strength impaired arms and no trunk function performed six upper body isometric strength tests and three 10 m sprints in their rugby wheelchair. All strength measures correlated with 2 m and 10 m sprint times (r ≥ -0.43; p ≤ 0.0005) and were entered into k-means cluster analyses with 4-clusters (to mirror the current International Wheelchair Rugby Federation [IWRF] system) and 3-clusters. The 3-cluster structure provided a more valid structure than both the 4-cluster and existing IWRF system, as evidenced by clearer differences in strength (Effect sizes [ES] ≥ 1.0) and performance (ES ≥ 1.1) between adjacent clusters and stronger mean silhouette coefficient (0.64). Subsequently, the 3-cluster structure for classifying proximal arm strength impairment would result in less overlap between athletes from adjacent classes and reduce the likelihood of athletes being disadvantaged due to their impairment. This study demonstrated that the current battery of isometric strength tests and cluster analyses could facilitate the evidence-based development of classifying proximal arm strength impairment in WR.

Cluster analysis of impairment measures to inform an evidence-based classification structure in RaceRunning, a new World Para Athletics event for athletes with hypertonia, ataxia or athetosis

RaceRunning enables athletes with limited or no walking ability to propel themselves independently using a three-wheeled frame that has a saddle, handle bars and a chest plate. For RaceRunning to be included as a para athletics event, an evidence-based classification system is required. This study assessed the impact of trunk control and lower limb impairment measures on RaceRunning performance and evaluated whether cluster analysis of these impairment measures produces a valid classification structure for RaceRunning. The Trunk Control Measurement Scale (TCMS), Selective Control Assessment of the Lower Extremity (SCALE), the Australian Spasticity Assessment Scale (ASAS), and knee extension were recorded for 26 RaceRunning athletes. Thirteen male and 13 female athletes aged 24 (SD = 7) years participated. All impairment measures were significantly correlated with performance (rho = 0.55-0.74). Using ASAS, SCALE, TCMS and knee extension as cluster variables in a two-step cluster analysis resulted in two clusters of athletes. Race speed and the impairment measures were significantly different between the clusters (p < 0.001). The findings of this study provide evidence for the utility of the selected impairment measures in an evidence-based classification system for RaceRunning athletes.

Understanding the Impact of Trunk and Arm Impairments on Wheelchair Rugby Performance During Competition

Purpose: To determine the effect of trunk and arm impairments on physical and technical performance during wheelchair rugby (WR) competition. Methods: Thirty-one highly trained WR players grouped according to their trunk (no trunk [NT]; some trunk [T] function) and arm impairments (poor, moderate, and good arm function) participated in 5 WR matches. Players’ physical (wheelchair mobility) and technical (ball handling) activities were analyzed using an indoor tracking system and video analysis, respectively. Results: Trunk impairment explained some of the variance in physical (10.6–23.5%) and technical (16.2–33.0%) performance. T covered more distance, had more possession, scored more goals, and received and made more passes yet spent less time at low speeds and performed fewer inbounds than NT (≤.05). Arm impairment explained some of the variance in all physical (16.7–47.0%) and the majority of technical (13.1–53.3%) performance measures. Moderate and good arm function covered more distance, reached higher peak speeds, spent more time in higher speed zones, scored more goals, had more possession, and received and made more passes, with a higher percentage of 1-handed and long passes, than poor arm function. Good arm function also received more passes and made a higher percentage of 1-handed passes and defensive blocks than moderate arm function (P ≤ .05). Conclusions: Arm impairment affects a greater number of physical and technical measures of performance specific to WR than trunk impairment during competition. Having active finger function (good arm function) yielded no further improvements in physical performance but positively influenced a small number of technical skills.

Intensity level and on-court role of wheelchair rugby players during competition

BACKGROUND

This study aims at quantifying the level of physical activity of wheelchair rugby players during matches in order to compare defensives players (DP) and offensives players (OP) profiles. Our hypothesis is that OP would present a higher energy expenditure and intensity level values during matches than DP, due to specific actions according to the on-court role.

METHODS

Fifty-two players, including 24 DP and 28 OP (mean age of 34±9 years), from eight French teams involved in the national elite championship and in the French national cup, participated. The seven wheelchair rugby players' classes were differentiated from 0.5 points (most severe deficiencies) to 3.5 points (less severe deficiencies). DP and OP were regrouped from 0.5 to 1.5 points and from 2 to 3.5 points, respectively. Energy expenditure (in kcal), intensity level (in metabolic equivalent of task) and physical activity time (in minutes) of wheelchair rugby players during competition were evaluated.

RESULTS

Statistical analysis between DP and OP showed a significant difference in vigorous activity time with a higher vigorous activity time for OP than DP; P<0.007), associated with higher mean intensity level for OP vs. DP (4.3±1.0 METs vs. 3.8±0.9 METs respectively; P=0.049). No significant differences between DP and OP were found for active energy expenditure (385±158 kcal vs. 446±199 kcal, for DP and OP respectively) during matches.

CONCLUSIONS

This study highlighted significantly different wheelchair rugby player profiles between competing DP and OP for the time spent in high intensity and intensity level. Offensive players were more explosive during a match than DP; therefore, training should be adapted accordingly to their roles.

How does the ball influence the performance of change of direction and sprint tests in para-footballers with brain impairments? Implications for evidence-based classification in CP-Football

The aims of this study were: i) to analyze the reliability and validity of three tests that require sprinting (10 m, 25 m, 40 m), accelerations/decelerations (Stop and Go Test) and change of direction (Illinois Agility Test), with and without ball, in para-footballers with neurological impairments, and ii) to compare the performance in the tests when ball dribbling is required and to explore the practical implications for evidence-based classification in cerebral palsy (CP)-Football. Eighty-two international para-footballers (25.2 ± 6.8 years; 68.7 ± 8.3 kg; 175.3 ± 7.4 cm; 22.5 ± 2.7 kg·m-2), classified according to the International Federation of Cerebral Palsy Football (IFCPF) Classification Rules (classes FT5-FT8), participated in the study. A group of 31 players without CP was also included in the study as a control group. The para-footballers showed good reliability scores in all tests, with and without ball (ICC = 0.53-0.95, SEM = 2.5-9.8%). Nevertheless, the inclusion of the ball influenced testing reproducibility. The low or moderate relationships shown among sprint, acceleration/deceleration and change of direction tests with and without ball also evidenced that they measure different capabilities. Significant differences and large effect sizes (0.53 < ηp2 < 0.97; p < 0.05) were found when para-footballers performed the tests with and without dribbling the ball. Players with moderate neurological impairments (i.e. FT5, FT6, and FT7) had higher coefficients of variation in the trial requiring ball dribbling. For all the tests, we also obtained between-group (FT5-FT8) statistical and large practical differences (ηp2 = 0.35-0.62, large; p < 0.01). The proposed sprint, acceleration/deceleration and change of direction tests with and without ball may be applicable for classification purposes, that is, evaluation of activity limitation from neurological impairments, or decision-making between current CP-Football classes.