What you see is not what you get:The impact of vision impairment on judo performance

Paralympic sports provide opportunities for athletes with impairment to participate and excel in sport competitions. To compete in Paralympic sports, all athletes must undergo classification to determine whether they are eligible to compete and to allocate eligible athletes to different sport classes. Classification criteria need to be based on scientific evidence showing the relationship between impairment and performance. Judo is a Paralympic sport for athletes with vision impairment (VI), which does not yet have an evidence-based classification system in place. The aim of this thesis was therefore to examine the impact of vision impairment on performance in judo. The results of this thesis suggested that vision impairment impacts performance in judo, both when starting without and with a grip in place. On the basis of the results of this thesis, new classification criteria for VI judo are currently proposed and being discussed by the International Blind Sports Federation in consultation with the wider VI judo community. The proposed changes include new minimum impairment criteria as well as split of VI judo competition into separate sport classes for partially sighted and functionally blind judokas. Besides providing practical recommendations for the organisation of judo for individuals with vision impairment, the current thesis exemplifies the remarkable capabilities of skilled performers to functionally adapt under suboptimal visual conditions

Fight without sight:The contribution of vision to judo performance

Objective: Although vision is typically considered the predominant sense for guiding performance, there are sports for which other senses are believed to be as important, if not more important than vision. Accordingly, in Paralympic judo, athletes with different degrees of vision impairment (VI) compete together based on the assumption that vision does not influence judo performance, as long as judokas start the match with their grip in place. The aim of this research was to test this assumption. Method: We conducted two studies. In the first we analysed data from two major recent VI judo competitions to compare the relative performance of blind and partially sighted athletes when competing against each other. In the second study, twenty-four able-sighted players competed in practice matches in sighted and blindfolded conditions. Results: In Study 1, we demonstrated that blind judokas win far less medals in VI judo competitions than their partially sighted opponents. In study 2, a significant performance advantage was found for sighted judokas fighting against blindfolded opponents. Conclusions: Vision enhances judo performance, even when judokas start the match with their grip in place. These findings suggest that it would be desirable to take measures to make VI judo competition fairer to those who are most severely impaired

The Development of Evidence-Based Classification of Vision Impairment in Judo: A Delphi Study

Objective: Most para-sports group athletes into “classes” to compete against others with similar activity limitations. Judokas with vision impairment (VI) instead all compete in the same class irrespective of their level of impairment. There is considerable controversy whether this approach represents a legitimate way to structure judo competition. The aim of this study was to establish expert opinion on the requirements for an evidence-based classification system for VI judo.Methods: A panel of 18 athletes, coaches, and administrators participated in a three-round Delphi review process. Expert opinions were canvased for a large range of issues related to classification in judo. Between rounds, results were summarized and further questions were asked on topics where consensus was not reached across experts.Results: The panel expressed that: (i) blind and partially sighted athletes should not compete against each other in the same class; (ii) additional measures of visual function might be needed to accurately evaluate an athlete’s impairment; (iii) the minimum impairment criteria (MIC) should represent a more severe level of impairment to ensure that all those included possess a level of VI that indeed decreases performance in judo; and (iv) legitimate competition could be undermined by some athletes intentionally underperforming on classification tests. The panel identified six additional measures of visual function which are not currently measured but are likely to impact judo performance, and six aspects of judo performance which are most likely impacted by VI.Conclusion: Experts in the field of VI judo expressed a need to change the manner in which VI judokas are classified. This study outlines a model for establishing the impairment–performance relationship and guides the development of evidence-based classification for VI judo

The Relationship Between Visual Function and Performance in Para Swimming

Background- Paralympic swimmers with vision impairment (VI) currently compete in one of the three classes depending on their visual acuity (VA) and/or visual field. However, there is no evidence to suggest that a three-class system is the most legitimate approach for classification in swimming, or that the tests of VA and visual field are the most suitable. An evidence-based approach is required to establish the relationship between visual function and performance in the sport. Therefore, the aim of this study was to establish the relationship between visual function and performance in VI Para swimming. The swimming performance of 45 elite VI swimmers was evaluated during international competitions by measuring the total race time, start time, clean swim velocity, ability to swim in a straight line, turn time, and finish time. Visual function was measured using a test battery that included VA, contrast sensitivity, light sensitivity, depth perception, visual search, and motion perception. Results- Results revealed that VA was the best predictor of total race time (r = 0.40, p  0.54). Conclusions- Results suggest that legitimate competition in VI swimming requires one class for partially sighted and another for functionally blind athletes

Combat as an Interpersonal Synergy:An Ecological Dynamics Approach to Combat Sports

In combat sports, athletes continuously co-adapt their behavior to that of the opponent. We consider this interactive aspect of combat to be at the heart of skilled performance, yet combat sports research often neglects or limits interaction between combatants. To promote a more interactive approach, the aim of this paper is to understand combat sports from the combined perspective of ecological psychology and dynamic systems. Accordingly, combat athletes are driven by perception of affordances to attack and defend. Two combatants in a fight self-organize into one interpersonal synergy, where the perceptions and actions of both athletes are coupled. To be successful in combat, performers need to manipulate and take advantage of the (in)stability of the system. Skilled performance in combat sports therefore requires brinkmanship: combatants need to be aware of their action boundaries and purposefully act in meta-stable regions on the limits of their capabilities. We review the experimental literature to provide initial support for a synergetic approach to combat sports. Expert combatants seem able to accurately perceive action boundaries for themselves and their opponent. Local-level behavior of individual combatants has been found to lead to spatiotemporal synchronization at the global level of a fight. Yet, a formal understanding of combat as a dynamic system starting with the identification of order and control parameters is still lacking. We conclude that the ecological dynamics perspective offers a promising approach to further our understanding of skilled performance in combat sports, as well as to assist coaches and athletes to promote optimal training and learning

Effect of vision impairment on match-related performance and technical variation in attacking moves in Paralympic judo

In Paralympic judo for athletes with vision impairment (VI judo) all eligible athletes (i.e. B1, B2 and B3 classes) compete against each other in the same competition. Evidence suggests that athletes with more impairment may be disadvantaged, but that more sensitive measures of performance are necessary to understand the impact of impairment on performance. The aim of this study was to investigate the relationship between Para sport class and technical variation, time-motion variables, and performance in Paralympic judo. All 175 judo matches from the Rio 2016 Paralympic Games were analysed across 129 competitors (82 male and 47 female). The main results indicated that athletes who demonstrated less technical variation also experienced less competitive success, with the functionally blind athletes (class B1) demonstrating less technical variation than partially sighted (class B2 and B3) athletes (p  0.05). We conclude that measures of technical variation are sensitive to differences in impairment and are suitable for studies that investigate the impairment-performance relationship in VI judo. Results further confirm that some athletes with impairment are disadvantaged under the current rules of VI judo

May the best-sighted win? The relationship between visual function and performance in Para judo

This study aimed to establish the optimal cut-off point(s) between classes in a new, evidence-based classification system for VI judo. We collected results from international VI judo competitions held between 2012 and 2018. Data on visual acuity (VA) and visual field (VF) measured during classification were obtained. Performance was determined by calculating a win ratio for each athlete. VA was significantly associated with judo performance (r = −.33, p <.001), VF was not (r =.30, p =.15). Decision tree analysis suggested to split the data into two groups with a VA cut-off of 2.5 logMAR units. Stability assessment using bootstrap sampling suggested a split into two groups, but showed considerable variability in the cut-off point between 2.0 and 3.5 logMAR. We conclude that to minimise the impact of impairment on the outcome of competition, VI judo should be split into two sport classes to separate partially sighted from functionally blind athletes. To establish an exact cut-off point and to decide if other measures of visual function need to be included, we argue for continued research efforts together with careful evaluation of research results from a multidisciplinary perspective

The Effect of Vision Impairment on Competitive and Technical-Tactical Performance in Judo: Is the Present System Legitimate?

In judo competition for visual impairment, athletes of different classes compete against each other in the same category; B1 athletes are totally blind, whereas B2 and B3 athletes are partially sighted. To test for potential competition disparities due a single category of athletes, this study aimed to compare competitive and technical-tactical performance in visually impaired judo athletes with different degrees of visual impairment. The authors analyzed 340 judo matches from the 2012 and 2016 Paralympic Games. The scores, penalties, efficiency index, and types of medals were examined, as well as the technical variation and temporal structure. The main finding was that blind judo athletes presented lower scores (p .05; ES = 0.07-0.14). The odds ratio of a winning medal was 3.5-8 times less in blind athletes than in partially sighted athletes (p < .01). In conclusion, blind judo athletes presented lower competitive and technical-tactical performance than athletes with some residual functional vision. These findings provide support for the development of new evidence-based criteria for judo classification based on vision impairment

Assessment of Visual Function and Performance in Paralympic Judo for Athletes with Vision Impairment

SIGNIFICANCE Paralympic judo currently requires all athletes to compete against each other in one class irrespective of their level of vision impairment (VI). Recent evidence suggests that multiple classes are required to enhance fairness, yet it remains unclear how many classes are necessary and what vision tests should be used to define those classes. PURPOSE The aim of this study was to quantify the relationship between vision and performance in judo for individuals with VI. The results were expected to inform the development of evidence-based criteria to structure Paralympic judo competition. METHODS The visual function of 53 elite VI judokas was assessed using a test battery that included tests of visual acuity (VA), contrast sensitivity, light sensitivity, depth perception, motion perception, visual search, and central visual field. Performance was assessed by measuring the ratio of fights won across all competitions the participants took part in in the 2 years before and after vision testing. Pearson correlation coefficients and decision tree analyses were used to determine the relationship between vision and performance. Partial correlations were also conducted to determine the unique ability of each measure of visual function to predict judo performance. RESULTS Visual acuity was the best predictor of judo performance and remained the only visual function related to performance when controlling for correlations between VA and other visual functions. Decision tree analyses suggested to split athletes into two groups for more legitimate competition, using a cutoff point around 2.6 logMAR. Within each of the two resulting subgroups, no correlations remained between any of the visual functions and performance. CONCLUSIONS The results of this study suggest that VI judo competition should be split into separate categories for partially sighted and functionally blind athletes. The inclusion of visual functions in addition to VA does not improve the ability to predict performance in VI judo