Classifying motor coordination impairment in Para swimmers with brain injury

Evaluating the Validity of Tests to Predict Sprint and Change of Direction Speed in Para-Athletes With Brain Impairments

Maximum running speed is a performance determinant in para-athletics and cerebral palsy football. Sixty international para-athletes with brain impairments completed five activity-limitation tests (standing broad jump, four bounds for distance, split jumps, 10-m speed skip, and running in place) and two criterion tests (40-m sprint and modified agility test). The same three tests (standing broad jump, four bounds for distance, and 10-m speed skip) that correlated with running performance in nondisabled runners (.67 < r < -.82; p < .05; 75% of variance) also correlated in para-athletes with brain impairments (.41 < r < -.62; p < .01; 55% of variance). Standing broad jump, four bounds for distance, split jumps, and running in place also correlated with change-of-direction speed (.43 < r < -.63; p < .01; 58% of variance). Results indicate that methods of classification for para-athletics with nondisabled runners are also valid with para-athletes with brain impairments, and new sport-specific relationships were found for assessing the performance of rapid and short sprints toward different directions, specific of a team para-sport like cerebral palsy football.

Portable Touchscreen Assessment of Motor Skill: A Registered Report of the Reliability and Validity of EDNA MoTap

Portable and flexible administration of manual dexterity assessments is necessary to monitor recovery from brain injury and the effects of interventions across clinic and home settings, especially when in-person testing is not possible or convenient. This paper aims to assess the concurrent validity and test-retest reliability of a new suite of touchscreen-based manual dexterity tests (called EDNA™MoTap) that are designed for portable and efficient administration. A minimum sample of 49 healthy young adults will be conveniently recruited. The EDNA™MoTap tasks will be assessed for concurrent validity against standardized tools (the Box and Block Test [BBT] and the Purdue Pegboard Test) and for test-retest reliability over a 1- to 2-week interval. Correlation coefficients of r > .6 will indicate acceptable validity, and intraclass correlation coefficient (ICC) values > .75 will indicate acceptable reliability for healthy adults. The sample were primarily right-handed (91%) adults aged 19 and 34 years (M = 24.93, SD = 4.21, 50% female). The MoTap tasks did not demonstrate acceptable validity, with tasks showing weak-to-moderate associations with the criterion assessments. Some outcomes demonstrated acceptable test-retest reliability; however, this was not consistent. Touchscreen-based assessments of dexterity remain relevant; however, there is a need for further development of the EDNA™MoTap task administration.

An Overview of Machine Learning Applications in Sports Injury Prediction

Use injuries, i.e., injuries caused by repetitive strain on the body, represent a serious problem in athletics that has traditionally relied on historic datasets and human experience for prevention. Existing methodologies have been frustratingly slow at developing higher precision prevention practices. Technological advancements have permitted the emergence of artificial intelligence and machine learning (ML) as promising toolsets to enhance both injury mitigation and rehabilitation protocols. This article provides a comprehensive overview of recent advances in ML techniques as they have been applied to sports injury prediction and prevention. A comprehensive literature review was conducted searching PubMed/Medline, Institute of Electrical and Electronics Engineers (IEEE)/Institute of Engineering and Technology (IET), and ScienceDirect. Ovid Discovery and Google Scholar were used to provide additional aggregate results and a grey literature search. A focus was placed on papers published from 2017 to 2022. Algorithms of interest were limited to K-Nearest Neighbor (KNN), K-means, decision tree, random forest, gradient boosting and AdaBoost, and neural networks. A total of 42 original research papers were included, and their results were summarized. We conclude that given the current lack of open source, uniform data sets, as well as a reliance on dated regression models, no strong conclusions about the real-world efficacy of ML as it applies to sports injury prediction can be made. However, it is suggested that addressing these two issues will allow powerful, novel ML architectures to be deployed, thus rapidly advancing the state of this field, and providing validated clinical tools.

Impact of maximal strength training on countermovement jump phase characteristics in athletes with cerebral palsy

Analysis of the countermovement jump (CMJ) force-time curve phases provides insight into athlete neuromuscular function and methods by which jump height improves in response to training. A CMJ phase analysis and the dynamic strength index (DSI) have yet to be explored in athletes with cerebral palsy (CP). This study aimed to address this knowledge gap. Eleven state- to international-level athletes with CP completed a pre-post maximal strength training intervention with waitlist control. CMJ was assessed via force plate pre/post baseline and after the 12-week intervention. Following the intervention, CMJ height, takeoff velocity, and concentric phase peak and mean force, impulse and mean acceleration improved significantly (p = 0.006-0.001). No changes were observed in any eccentric braking phase variable (p = 0.79-0.13), while DSI lowered (p = 0.03). In athletes with CP, strength training increased CMJ concentric phase peak and mean force and impulse, increasing velocity and acceleration and therefore jump height. DSI lowered due to moderate and small increases in isometric mid-thigh pull and CMJ peak force, respectively. Unlike in non-disabled athletes, strength training did not alter any eccentric phase variable; therefore, other modalities may be required to further optimize jumping performance in athletes with CP.

Not all Forms of Muscle Hypertonia Worsen With Fatigue: A Pilot Study in Para Swimmers

In hypertonic muscles of patients with upper motor neuron syndrome (UMNS), investigation with surface electromyography (EMG) with the muscle in a shortened position and during passive muscle stretch allows to identify two patterns underlying hypertonia: spasticity and spastic dystonia. We recently observed in Para swimmers that the effect of fatigue on hypertonia can be different from subject to subject. Our goal was, therefore, to understand whether this divergent behavior may depend on the specific EMG pattern underlying hypertonia. We investigated eight UMNS Para swimmers (five men, mean age 23.25 ± 3.28 years), affected by cerebral palsy, who presented muscle hypertonia of knee flexors and extensors. Muscle tone was rated using the Modified Ashworth Scale (MAS). EMG patterns were investigated in rectus femoris (RF) and biceps femoris (BF) before and after two fatiguing motor tasks of increasing intensity. Before the fatiguing tasks, two subjects (#2 and 7) had spasticity and one subject (#5) had spastic dystonia in both RF and BF. Two subjects (#3 and 4) showed spasticity in RF and spastic dystonia in BF, whereas one subject (#1) had spasticity in RF and no EMG activity in BF. The remaining two subjects (#6 and 8) had spastic dystonia in RF and no EMG activity in BF. In all the 16 examined muscles, these EMG patterns persisted after the fatiguing tasks. Spastic dystonia increased (p &lt; 0.05), while spasticity did not change (p &gt; 0.05). MAS scores increased only in the muscles affected by spastic dystonia. Among the phenomena possibly underlying hypertonia, only spastic dystonia is fatigue-dependent. Technical staff and medical classifiers should be aware of this specificity, because, in athletes with spastic dystonia, intense and prolonged motor activity could negatively affect competitive performance, creating a situation of unfairness among Para athletes belonging to the same sports class.

Association between upper-limb isometric strength and handcycling performance in elite athletes

This study investigated the association among isometric upper-limb strength of handcyclists and sport-specific performance outcomes. At two international events, 62 athletes were tested on upper-limb strength, measured with an isometric-strength setup and with Manual Muscle Test (MMT). Horizontal force (Fz), effectiveness, rate of development, variability, and asymmetries were calculated for upper-limb pull and push. Performance measures were mean (POmean) and peak (POpeak) 20-s sprint power output and average time-trial velocity (TTvelocity). Regression models were conducted to investigate which pull and push strength variables associated strongest with performance measures. Additional regression analyses were conducted with an MMT sum score as predictor. Push and pull Fz showed the strongest associations with all outcomes. Combined push and pull Fz explained (p < .001) 80-81% of variance of POmean and POpeak. For TTvelocity, only push Fz was included in the model explaining 29% of the variance (p < .001). MMT models revealed weaker associations with sprint PO (R2 = .38-.40, p < .001) and TTvelocity (R2 = .18, p = 0.001). The findings confirmed the relevance of upper-limb strength on handcycling performance and the significance of ratio-scaled strength measures. Isometric strength outcomes are adequate sport-specific indicators of impairment in handcycling classification, but future research should corroborate this notion and its potential to discriminate between sports classes.

Lower Limb Kinematic Coordination during the Running Motion of Stroke Patient: A Single Case Study

The purpose of this study was to clarify the lower limb joint motor coordination of para-athletes during running motion from frequency characteristics and to propose this as a method for evaluating their performance. The subject used was a 43-year-old male para-athlete who had suffered a left cerebral infarction. Using a three-dimensional motion analysis system, the angles of the hip, knee, and ankle joints were measured during 1 min of running at a speed of 8 km/h on a treadmill. Nine inter- and intra-limb joint angle pairs were analyzed by coherence and phase analyses. The main characteristic of the stroke patient was that there were joint pairs with absent or increased coherence peaks in the high-frequency band above 4 Hz that were not found in healthy subjects. Interestingly, these features were also observed on the non-paralyzed side. Furthermore, a phase analysis showed different phase differences between the joint motions of the stroke patient and healthy subjects in some joint pairs. Thus, we concluded there was a widespread functional impairment of joint motion in the stroke patient that has not been revealed by conventional methods. The coherence analysis of joint motion may be useful for identifying joint motion problems in para-athletes.

Passive drag in Para swimmers with physical impairments: Implications for evidence-based classification in Para swimming

The inherent hydrodynamic resistance force, or passive drag, of a swimmer directly influences how they move through the water. For swimmers with physical impairments, the strength of association between passive drag and swimming performance is unknown. Knowledge on this factor could improve the World Para Swimming classification process. This study established the relationship between passive drag and 100 m freestyle race performance in Para swimmers with physical impairments. Using a cross-sectional study design, an electrical-mechanical towing device was used to measure passive drag force in 132 international-level Para swimmers. There was a strong, negative correlation between normalized passive drag force and 100 m freestyle race speed in the combined participant cohort (ρ = -0.77, p < 0.001). Type of physical impairment was found to affect the relationship between passive drag and 100 m freestyle race speed when included in linear regression (R²  = 0.65, χ²  = 11.5, p = 0.025). These findings contribute to the body of evidence that passive drag can provide an objective assessment of activity limitation in Para swimmers with physical impairments. The effect of physical impairment type on the relationship between passive drag and swimming performance should be accounted for in Para swimming classification.

Improving the objectivity of the current World Para Swimming motor coordination test for swimmers with hypertonia, ataxia and athetosis using measures of movement smoothness, rhythm and accuracy

The current protocol for classifying Para swimmers with hypertonia, ataxia and athetosis involves a physical assessment where the individual's ability to coordinate their limbs is scored by subjective clinical judgment. The lack of objective measurement renders the current test unsuitable for evidence-based classification. This study evaluated a revised version of the Para swimming assessment for motor coordination, incorporating practical, objective measures of movement smoothness, rhythm error and accuracy. Nineteen Para athletes with hypertonia and 19 non-disabled participants performed 30 s trials of bilateral alternating shoulder flexion-extension at 30 bpm and 120 bpm. Accelerometry was used to quantify movement smoothness; rhythm error and accuracy were obtained from video. Para athletes presented significantly less smooth movement and higher rhythm error than the non-disabled participants (p < 0.05). Random forest algorithm successfully classified 89% of participants with hypertonia during out-of-bag predictions. The most important predictors in classifying participants were movement smoothness at both movement speeds, and rhythm error at 120 bpm. Our results suggest objective measures of movement smoothness and rhythm error included in the current motor coordination test protocols can be used to infer impairment in Para swimmers with hypertonia. Further research is merited to establish the relationship of these measures with swimming performance.

Establishing the reliability of instrumented trunk impairment assessment methods to enable evidence-based classification in Para swimming

This study examined the reliability of instrumented trunk assessment methods across two experiments to develop and improve evidence-based classification in Para swimming. Trunk coordination, range of motion (ROM), and strength were assessed in 38 non-disabled participants. Each test battery was completed on two occasions to determine inter-session reliability. Intra-session reliability was also determined in Experiment Two. Absolute agreement of two-way mixed intraclass correlation coefficients (ICC 3,1) was calculated to assess reliability. Standard errors of measurement (SEMs) were also reported to facilitate comparisons between different outcomes. Trunk coordination measures had low-to-moderate reliability (inter-session ICCs = 0.00-0.60; intra-session ICCs = 0.14-0.65) and variable SEMs (5-60%). Trunk ROM demonstrated moderate-to-excellent reliability (inter-session ICCs = 0.61-0.93; intra-session ICCs = 0.87-0.95) and good SEMs (<10%). Trunk strength measures demonstrated good-to-excellent reliability (ICCs = 0.87-0.98) and good SEMs (<10%). The strength values obtained for the load cell and hand-held dynamometer (HHD) were significantly different from each other with the HHD underestimating strength. Modifications provided in Experiment Two improved the reliability of strength and ROM assessments but did not improve coordination measures. Further research involving para swimmers is required to establish the validity of the methods.

Using Decision Trees to Support Classifiers' Decision-Making about Activity Limitation of Cerebral Palsy Footballers

This study aimed (1) to determine the appropriateness of using decision trees as a classification tool for determining the allocation of sport classes of para-footballers with "moderate vs. mild" cerebral palsy (CP) profiles of spastic diplegia/hemiplegia and ataxia/athetosis based on observational outcomes by international classifiers, and (2) to identify what key observational features were relevant to discriminating among different impairment levels. A sample of 16 experienced international classifiers from five world regions participated in this study, observing activity limitation of a final sample of 21 international CP footballers when performing 16 gross-motor and sports-specific tests for balance (n = 3), coordination (n = 5), running, accelerations and decelerations (n = 3), jumping (n = 4), and change of direction ability (n = 1). For the overall sample (336 observations), the model included eight decision nodes and 24 branches with 17 leaves, including side-step, side-stepping, and triple hop as the tests with the best sensitivity (precision = 67.0%). For those with spastic diplegia (64 observations: Two nodes, six branches with five leaves), the range of motion in the side-step test and the balance in the tandem walk tests correctly classified 89.1% of the observations. In those with athetosis and ataxia (96 observations), the model included five nodes, 15 branches, and 11 leaves (176 observations, precision = 86.5%). For those with spastic hemiplegia, a model containing two nodes, six branches, and five leaves had 90.9% accuracy, including observational features of balance in the side-step test and symmetry in the side-stepping test. The observational tool used in this study, based on the impact of specific impairment measurements of hypertonia, athetosis, and ataxia, can be used to determine which assessments are more appropriate for discriminating between functional profiles in para-footballers with CP.

Seasonal Changes in Breathing Pattern, Trunk Stabilization, and Muscular Power in Paralympic Swimmers

The purpose of this study was to monitor the changes in breathing pattern, trunk muscle stabilization, and upper-body muscular power in Paralympic swimmers throughout a competitive season over three time points: October (T1), March (T2), and August (T3). Six top-level Paralympic swimmers voluntarily participated in this study. The Friedman test, the Bonferroni-Dunn multiple comparison post hoc analysis, and Kendall's W concordance coefficient for the measure of effect were used. A significant difference was found in the breathing pattern, trunk stability, and upper-body power variables from the T1 to T3 season (p < .05). However, no significant changes were found in the T2 season. A long-term assessment of these fitness parameters may be of practical importance for better tailoring the training programs of top-level Paralympic swimmers.

Does sports-specific training improve measures of impairment developed for para sport classification? A multiple-baseline, single-case experiment

Conceptually, sports-specific training should not influence measures of impairment used to classify Para athletes. This study evaluated the extent to which measures of strength, range of movement and coordination developed for Para swimming classification changed in response to a performance-focused swimming programme. A five-phase multiple-baseline, single-case experimental research design was utilized. Three participants with cerebral palsy and high support needs completed the 64-week study, which included two 16-week performance-focused swimming training blocks. Swimming speed, isometric shoulder extension strength, shoulder flexion range of movement and upper limb coordination were monitored throughout.Interrupted Time-Series Simulation Method analysis demonstrated large, significant changes in swimming speed (m/s) during the first (d = 2.17; 95% CI 0.45-3.88; p = 0.01) and second (d = 2.59; 95% CI 1.66-3.52; p = 0.00) training blocks. In contrast, changes in strength, range of movement and coordination were predominantly trivial and non-significant. This was the first study to investigate training responsiveness of measures developed for Para sport classification. Results indicate that despite significantly improved swimming performance, impairment measures remained relatively stable, and therefore these measures of impairment may be valid for the purposes of Para swimming classification. Further research is required in elite athletes, different sports and different impairment types.

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.

Is impaired coordination related to match physical load in footballers with cerebral palsy of different sport classes?

Impaired coordination is a characteristic feature in cerebral palsy (CP) football players. This study aimed to determine the relationships of three coordination tests with match physical load during competition of para-footballers from different sport classes. Records from 259 para-footballers from 25 national teams were obtained in four international competitions held in 2018 and 2019. The three coordination tests were conducted prior to competition (i.e., rapid heel-toe, side-stepping, and split jumps), and physical match load was recorded by GPS devices during the real game: i.e., maximum/mean, total distance, distance covered at different speed zones, number of accelerations/decelerations at different intensities, and player load. FT1 and FT3 players have the lowest and highest performance in all the coordination tests, respectively, but inconclusive between-groups differences were obtained (p=0.022‒0.238). Split jumps and side-stepping tests are associated with the performance of moderate and high accelerations during competition (r = -0.20‒0.71; p<0.01). Significant correlations (r = 0.36‒0.71; p<0.01) were obtained between all the coordination measures. Coordination tests better discriminate those with more severe impairments and some evidence for the validity of the new CP football sport classes is provided. Further research is necessary to identify the portion of the variance in sports performance that coordination explains.

Modelling the age-related trajectory of performance in Para swimmers with physical, vision and intellectual impairment

This study is the first to provide information on the age-related trajectories of performance in Para swimmers with physical, vision and intellectual impairment. Race times from long-course swim meets between 2009 and 2019 were obtained for Para swimmers with an eligible impairment. A subset of 10 661 times from 411 Para swimmers were included in linear mixed effects modelling to establish the relationship between age and performance expressed relative to personal best time and world record time. The main findings were: (a) age has the most noticeable influence on performance between the ages of 12-20 years before performances stabilize and peak in the early to late twenties, (b) women have faster times relative to personal best and world record time than men during early adolescence and their performances stabilize, peak and decline at younger ages, and (c) Para swimmers from different sport classes show varying age-related trajectories in performance after maturation and when training-related factors are more likely to explain competitive swim performance. The results of this study can guide talent identification and development of Para swimmers at various stages of their career and help to inform decision-making on the allocation of sport class and sport class status in Para swimming classification.

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.

Measures of impairment applicable to the classification of Paralympic athletes competing in wheelchair sports: A systematic review of validity, reliability and associations with performance

A fundamental aspect of classification systems in Paralympic sport is having valid and reliable measures of impairment. However, minimal consensus exists for assessing impaired strength, coordination and range of motion. This review aimed to systematically identify measures of upper body strength, coordination and range of motion impairments that meet the requirements for use in evidence-based classification systems in wheelchair sports. Three electronic databases were searched from 2003 until 31 August 2019 for studies that assessed upper body function of participants and used a measurement tool that assessed strength, coordination or range of motion. The body of evidence for each identified measure was appraised using the Grading of Recommendations Assessment, Development and Evaluation framework. Twenty-three studies were included: ten measured strength and coordination, and six measured range of motion. There was "moderate" confidence in using isometric strength for assessing strength impairment. Tapping tasks for the assessment of coordination impairment received a "low" confidence rating. All other identified measures of coordination and range of motion impairment received a "very low" confidence rating. Several potential measures were identified for assessing upper body strength, coordination and range of motion impairments. Further research is warranted to investigate their use for classification in Paralympic wheelchair sports.

Maximal Fully Tethered Swim Performance in Para Swimmers With Physical Impairment

The assessment of swimming propulsion should be a cornerstone of Paralympic swimming classification. However, current methods do not objectively account for this component.

PURPOSE

To evaluate the swimming propulsion of swimmers with and without physical impairment using a 30-second maximal fully tethered freestyle swim test.

METHODS

Tethered forces were recorded during maximal fully tethered swimming in 80 competitive swimmers with (n = 70) and without (n = 10) physical impairment. The relationships between absolute and normalized tether forces and maximal freestyle swim speed were established using general additive models.

RESULTS

Para swimmers with physical impairment had lower absolute and normalized tether forces than able-bodied swimmers, and there were moderate positive correlations found between tether forces and sport class (τ = .52-.55, P < .001). There was a nonlinear relationship between tether force and maximal freestyle swim speed in the participant cohort (adjusted R2 = .78-.80, P < .001). Para swimmers with limb deficiency showed stronger relationships between tether force and maximal freestyle swim speed (adjusted R2 = .78-.82, P < .001) than did Para swimmers with hypertonia (adjusted R2 = .54-.73, P < .001) and impaired muscle power (adjusted R2 = .61-.70, P < .001).

CONCLUSIONS

Physical impairments affect Para swimmers' tether forces during maximal fully tethered freestyle swimming, explaining a significant proportion of their activity limitation. It is recommended that maximal fully tethered swimming be included in Paralympic swimming classification as an objective assessment of swimming propulsion.