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

Abstract

This study aimed to establish the optimal cutoff 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 cutoff of 2.5 logMAR units. Stability assessment using bootstrap sampling suggested a split into two groups, but showed considerable variability in the cutoff 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 cutoff 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 relationship between visual function and performance in Para-swimming

“…All participants provided written informed consent prior to participation. Parental consent was obtained for participants aged under 18…”

“…The aim of the classi cation assessment is not to establish the exact level of VA, but rather to determine which sports class an athlete should be allocated to. In particular, classi ers sometimes do not establish the exact level of VA or visual eld if they have already established the class the athlete will be allocated, especially when VA is worse than 2.6 logMAR and so the classi er knows that the athlete will be in the S11 class irrespective of any further testing [18,20]. Clearly, to properly establish the relationship between visual function and performance, a study is necessary that accurately measures different aspects of vision.…”

“…Research in VI ri e shooting demonstrated that only one class was necessary in that sport, because functionally blind athletes could perform just as well as athletes with much less impairment (presumably because they can effectively exploit the auditory feedback used in the sport to guide the ri e; [7][8][9][10][11][12]). Note that research has also begun in other VI sports including football [13,14], judo [15][16][17][18][19][20], skiing [21,22], athletics [23], goalball [24] and swimming [6].…”

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

“…This is especially clear in interactive sports, where athletes need to coadapt their own behaviours to that of their opponent (Hristovski et al, 2012;Pinder et al, 2011). To outperform a direct opponent (e.g., pass a defender in soccer, or strike an opponent in boxing), athletes may need to operate in metastable performance regions, where multiple competing modes of action co-exist and small perturbations can shift the dynamics of the contest either way (Duarte et al, 2012;Hristovski et al, 2006;Kimmel & Rogler,2018;K. Krabben et al, 2019b).The key implication for athletes in interactive sports is that a wider repertoire of movements will provide more options during a match and likely be associated with greater competitive success (Krabben et al, 2019b).…”

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

“…Karalis [24] argued that decision trees are a way to express the rules underlying data with hierarchical, sequential structures that recursively partition the data. Since they are commonly used for calculating probabilities and help in decision making, this method helps classifiers to assess the relationship between impairment function and para-athlete performance, as it has been already shown in para-shooting [25] and para-judo [26] for athletes with visual impairment. In CP football, data envelopment analysis [15] and cluster analysis [14] have been used as classification methods, while, to the best of the authors' knowledge, the decision tree has never been applied.…”