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

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

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

In Paralympic sport, classification of impairment is needed to prevent a one-sided and predictable outcome of competition, in which the least impaired athlete has the best chance to win. To develop evidence-based classification in wheelchair rugby, the impact of trunk impairment, measured by the Trunk Impairment Classification (TIC), on performance-determining activities was assessed. Arm impairment was analyzed as a covariant. Fifty-five athletes, 21 with TIC score 0, 13 with TIC score 0.5, 11 with TIC score 1.0, and 10 with TIC score 1.5 performed standardized sport-specific activities. A multiple step forward regression analysis was performed for all activities to assess the relative impact of trunk and arm impairment on performance. Trunk impairment was the most important factor for tilting the chair and acceleration in the first 2 m. The explained variance of the performance by trunk and arm impairment ranged from 23% for acceleration in the first meter, to 37% for sprint momentum, the tilt test left, and the time to cover 3 and 4 m. This study shows that athletes with limited trunk impairment are more proficient in wheelchair rugby than athletes with severe trunk impairment.

Reliability of the revised wheelchair rugby trunk impairment classification system.

STUDY DESIGN: Observational, cross-sectional. OBJECTIVES: A new classification system for trunk impairment in wheelchair rugby was introduced in 2010. It consists of 10 tests, arranged in an algorithm, to assign four different trunk scores (0, 0.5, 1.0 or 1.5) to athletes. The purpose of this study was to assess the inter-rater reliability of this classification system. SETTING: National competition for wheelchair rugby and wheelchair basketball in the Netherlands and Belgium. METHODS: Three experienced wheelchair rugby classifiers independently assigned trunk scores to wheelchair rugby and wheelchair basketball athletes in two sessions. After each session, test descriptions were adjusted. The inter-rater reliability was evaluated by determining the agreement and Fleiss Kappa. RESULTS: In the first session, all classifiers agreed on the trunk score in 13 out of 16 athletes; the overall Kappa was 0.76 (P<0.001). The Kappa per trunk score ranged from 0.29 to 1. Four test descriptions were adjusted after the first session. In the second session, there was an agreement in trunk score between the classifiers in 15 out of 21 athletes. The overall Kappa was 0.75 (P<0.0001), and the Kappa per trunk scores ranged from 0.58 to 0.92. After the second session, two test descriptions were improved. CONCLUSION: The revised classification system for trunk impairment in wheelchair rugby showed a adequate inter-rater reliability for the allocation of trunk scores.

International Paralympic Committee position stand--background and scientific principles of classification in Paralympic sport.

The Classification Code of the International Paralympic Committee (IPC), inter alia, mandates the development of evidence-based systems of classification. This paper provides a scientific background for classification in Paralympic sport, defines evidence-based classification and provides guidelines for how evidence-based classification may be achieved. Classification is a process in which a single group of entities (or units) are ordered into a number of smaller groups (or classes) based on observable properties that they have in common, and taxonomy is the science of how to classify. Paralympic classification is interrelated with systems of classification used in two fields: Health and functioning. The International Classification of Functioning, Disability and Health is the most widely used classification in the field of functioning and health. To enhance communication, Paralympic systems of classification should use language and concepts that are consistent with the International Classification of Functioning, Disability and Health. Sport. Classification in sport reduces the likelihood of one-sided competition and in this way promotes participation. Two types of classification are used in sport-performance classification and selective classification. Paralympic sports require selective classification systems so that athletes who enhance their competitive performance through effective training will not be moved to a class with athletes who have less activity limitation, as they would in a performance classification system. Classification has a significant impact on which athletes are successful in Paralympic sport, but unfortunately issues relating to the weighting and aggregation of measures used in classification pose significant threats to the validity of current systems of classification. To improve the validity of Paralympic classification, the IPC Classification Code mandates the development of evidence-based systems of classification, an evidence-based system being one in which the purpose of the system is stated unambiguously; and empirical evidence indicates the methods used for assigning class will achieve the stated purpose. To date, one of the most significant barriers to the development of evidence-based systems of classification has been absence of an unambiguous statement of purpose. To remedy this, all Paralympic systems of classification should indicate that the purpose of the system is to promote participation in sport by people with disabilities by minimising the impact of eligible impairment types on the outcome of competition. Conceptually, in order to minimise the impact of impairment on the outcome of competition, each classification system should: describe eligibility criteria in terms of: type of impairment and severity of impairment; describe methods for classifying eligible impairments according to the extent of activity limitation they cause. To classify impairments according to the extent of activity limitation they cause requires research that develops objective, reliable measures of both impairment and activity limitation and investigates the relative strength of association between these constructs in a large, racially representative sample. The paper outlines a number of objective principles that should considered when deciding how many classes a given sport should have: the number of classes in a sport should not be driven by the number of athletes in a sport at a single time point.

Physical fitness profile of elite athletes with intellectual disability.

UNLABELLED: The aim of this study was to investigate the physical fitness profile of high-performance athletes with intellectual disability (ID) in comparison with able-bodied individuals. METHODS: Participants were 231 male and 82 female athletes. All evaluations were done using the EUROFIT physical fitness test. RESULTS: In comparison with population data, both male and female athletes with ID score better for flexibility and upper body muscle endurance, but have similar or lower values for running speed, speed of limb movement, and strength measures. Compared with age-matched physical education students, male athletes with ID score better for running speed and flexibility, and worse for strength. Female athletes with ID score not different from able-bodied individuals for flexibility, running speed, and upper body muscle endurance, but worse for strength measures. Athletes with ID also have poorer cardio respiratory endurance capacity compared with sportive peers without ID. Furthermore, male athletes have a more differentiated profile depending upon their sports discipline, compared with female athletes. CONCLUSION: It can be concluded that high-performance athletes with ID reach physical fitness levels that are equal to or lower than those of able-bodied sportive counterparts. Further research should investigate the importance of reduced muscle strength to be the limiting factor.

Influence of isocapnic hyperpnoea on maximal arm cranking performance.

Isocapnic hyperpnoea has been shown to reliably produce fatigue of the diaphragm. The aim of the present study was to investigate whether incremental isocapnic hyperpnoea (IH(incr)) impairs the arm exercise performance and alters the breathing pattern during subsequent maximal incremental arm cranking. Nine healthy volunteers performed an arm cranking test with prior IH(incr) (AC(IH)) and without prior IH(incr) (AC(control)). Minute ventilation ( V(E)), tidal volume ( V(T)), breathing frequency ( f(b)), O(2) uptake ( VO(2)), CO(2) elimination ( VCO(2)), respiratory exchange ratio (RER) and end-tidal partial pressure of CO(2) ( P(ET)CO(2)) were measured at three different time intervals ( t(1): the average of the 3.30th min to the 6.30th min, t(2): 1 min before the end, t(3): peak value) and expressed as mean (SD). V(T) at t(1) and at t(3) was significantly ( P<0.05) lower during AC(IH) [AC(control): t(1): 1.3 (0.5) l, t(p): 1.9 (0.3) l; AC(IH): t(1): 1.1 (0.3) l, t(p): 1.6 (0.3) l]. f(b) at t(1) and t(2) was significantly ( P<0.05) higher during AC(IH) [AC(control): t(1): 23 (4) breaths min(-1), t(2): 42 (14) breaths min(-1); AC(IH): t(1): 27 (5) breaths min(-1), t(2): 48 (14) breaths min(-1)]. The maximal voluntary ventilation (MVV), measured before and immediately after the IH(incr), demonstrated a small but significant decrease from 157 (15) l min(-1) to 150 (14) l min(-1) ( P<0.05) after the IH(incr). In conclusion, rapid shallow breathing occurred during maximal arm cranking exercise after IH(incr). The alteration was irrespective of the workload and had already occurred at the start of exercise.

Field test evaluation of aerobic, anaerobic, and wheelchair basketball skill performances.

Forty-six male wheelchair basketball players performed a set of field tests to evaluate aerobic capacity (25 m shuttle run), anaerobic capacity (30s sprint), and six specific wheelchair basketball skills. Overall test-retest reliability (n = 20) ranged from r = 0.65 to r = 0.97. To study the validity (criterion related evidence) of the shuttle run test, heart rate (HR) was recorded for 15 subjects, who also performed a continuous, multistage arm cranking exercise until volitional fatigue. Moderate to high correlations were calculated between shuttle run distances covered (1375 243,6 m) and VO2max (2208+/-461.6 mL/min) and POmax (93.8+/-17.97 W), measured during maximal arm cranking (respectively r = 0.64 and r = 0.87). Maximal HR during shuttle run (174.9+/-16.6 B/min) and arm cranking (169+/-14.21 B/min) were correlated (r = 0.78). High correlations between shuttle run test and anaerobic field tests, however, indicate high implication of anaerobic and wheelchair maneuverability performances. The 30 s sprint test was validated (n = 15) against a Wingate Anaerobic Test (WAnT) on a roller ergometer. Comparing distance (field test: 90+/-6.7 m) with mean power output (WAnT: 852.1+/-234.9 W) the correlation was r = 0.93. Principal components factor analysis identified 'wheelchair propulsion dynamics' and 'eye-hand-coordination' as the underlying constructs of the six skill proficiency measurements, accounting for 80.1% of the variance. In conclusion, the newly developed field test battery is a reliable and valid tool for anaerobic capacity and skill proficiency assessment in wheelchair basketball players.

Wheelchair propulsion efficiency: movement pattern adaptations to speed changes.

Low mechanical efficiency values in wheelchair propulsion are usually explained on the basis of the supply of force and power generated during the push phase. The purpose of this study is to analyze the movement and muscular activity pattern in handrim wheelchair propulsion, focusing on both the push and recovery phases. Data on cardiorespiratory and propulsion technique parameters were obtained from 40 wheelchair basketball players with extensive experience in wheelchair propulsion in six situations: two exercise levels (60% and 80% of individual VO2peak), and three velocities (1.11, 1.67, and 2.22 m.s-1) with constant power output on a treadmill. A two-factor analysis of variance with repeated measurements was applied with "exercise level" and "speed" as the main factors. A significant effect on gross mechanical efficiency was found when the velocity was increased from 1.67 to 2.22 m.s-1. Decreased mechanical efficiency could be explained by a significant change in the acceleration of the wheelchair-user system during recovery, caused by arm and trunk movements, inducing inertial forces to act on the wheelchair. Consequently, mechanical work increased significantly during the recovery phase. These findings indicate that studies on mechanical efficiency in wheelchair propulsion should not only be focussed on power supply during the push phase, but also on the movement pattern during recovery.

Wheelchair propulsion: functional ability dependent factors in wheelchair basketball players.

The aim of this study was to examine the user-related parameters, 1) force generation 2) maximal aerobic power and 3) propulsion technique, in respect to functional ability level [ISMWSF] wheelchair basketball classification: groups 1, 2 and 3) of 40 elite wheelchair basketball players. Isometric (position on the handrims = -30, 0 degrees, +30 degrees and +60 degrees) and dynamic force application (velocities = 0.56, 0.83 and 1.11 m.s-1) on the handrims (test 1) was measured by means of a computerised wheelchair simulator, with the subjects sitting in a standardised position. Each subject performed a maximal exercise test (test 2) on a motor driven treadmill at 1.67 m.s-1 and four subsequent submaximal tests (test 3) at two exercise levels (60 and 80% of individual VO2) and two velocities (1.11 and 2.22 m.s-1) with constant power output. In tests 2 and 3, cardiorespiratory and kinematic data were recorded simultaneously. Although no significant differences between functional ability groups were found in relation to force application on the handrims, three different force application strategies were observed (test 1). Maximal aerobic capacity and power output (test 2) differed significantly (p < 0.05) between groups 1 and 2 and between groups 1 and 3. No differences in mechanical efficiency were observed between the three functional ability groups, irrespective of changes in wheelchair velocity and external load (test 3). Propulsion technique was not proven to be functional ability dependent although remarkable differences in movement pattern were observed, especially during the recovery phase.