Differenze nella prestazione tecnico-tattica tra diverse categorie di atleti nel tennistavolo di alto livello

Nell’ambito della ricerca scientifica nel campo dello sport, la Performance Analysis si sta ritagliando un crescente spazio di interesse. Per Performance Analysis si intende l’analisi della prestazione agonistica sia dal punto di vista biomeccanico che dal punto di vista dell’analisi notazionale. In questa tesi è stata analizzata la prestazione agonistica nel tennistavolo attraverso lo strumento dell’analisi notazionale, partendo dallo studio degli indicatori di prestazione più importanti dal punto di vista tecnico-tattico e dalla loro selezione attraverso uno studio sull’attendibilità nella raccolta dati. L’attenzione è stata posta quindi su un aspetto tecnico originale, il collegamento spostamenti e colpi, ricordando che una buona tecnica di spostamento permette di muoversi rapidamente nella direzione della pallina per effettuare il colpo migliore. Infine, l’obbiettivo principale della tesi è stato quello di confrontare le tre categorie di atleti selezionate: alto livello mondiale maschile (M), alto livello junior europeo (J) ed alto livello mondiale femminile (F). La maggior parte delle azioni cominciano con un servizio corto al centro del tavolo, proseguono con una risposta in push (M) o in flik di rovescio (J). Il colpo che segue è principalmente il top spin di dritto dopo un passo pivot o un top di rovescio senza spostamento. Gli alteti M e J contrattaccano maggiormente con top c. top di dritto e le atlete F prediligono colpi meno spregiudicati, bloccando di rovescio e proseguendo con drive di rovescio. Attraverso lo studio della prestazione di atleti di categorie e generi diversi è possibile migliorare le scelte strategiche prima e durante gli incontri. Le analisi statistiche multivariate (modelli log-lineari) hanno permesso di validare con metodo scientifico sia le procedure già utilizzate in letteratura che quelle innovative messe a punto per la prima volta in occasione di questo studio.

Visual scanning in sports actions: comparison between soccer goalkeepers and judo fighters

Visual search and oculomotor behaviour are believed to be very relevant for athlete performance, especially for sports requiring refined visuo-motor coordination skills. Modern coaches believe that a correct visuo-motor strategy may be part of advanced training programs. In this thesis two experiments are reported in which gaze behaviour of expert and novice athletes were investigated while they were doing a real sport specific task. The experiments concern two different sports: judo and soccer. In each experiment, number of fixations, fixation locations and mean fixation duration (ms) were considered. An observational analysis was done at the end of the paper to see perceptual differences between near and far space. Purpose: The aim of the judo study was to delineate differences in gaze behaviour characteristics between a population of athletes and one of non athletes. Aspects specifically investigated were: search rate, search order and viewing time across different conditions in a real-world task. The second study was aimed at identifying gaze behaviour in varsity soccer goalkeepers while facing a penalty kick executed with instep and inside foot. Then an attempt has been done to compare the gaze strategies of expert judoka and soccer goalkeepers in order to delineate possible differences related to the different conditions of reacting to events occurring in near (peripersonal) or far (extrapersonal) space. Judo Methods: A sample of 9 judoka (black belt) and 11 near judoka (white belt) were studied. Eye movements were recorded at 500Hz using a video based eye tracker (EyeLink II). Each subject participated in 40 sessions for about 40 minutes. Gaze behaviour was considered as average number of locations fixated per trial, the average number of fixations per trial, and mean fixation duration. Soccer Methods: Seven (n = 7) intermediate level male volunteered for the experiment. The kickers and goalkeepers, had at least varsity level soccer experience. The vision-in-action (VIA) system (Vickers 1996; Vickers 2007) was used to collect the coupled gaze and motor behaviours of the goalkeepers. This system integrated input from a mobile eye tracking system (Applied Sciences Laboratories) with an external video of the goalkeeper’s saving actions. The goalkeepers took 30 penalty kicks on a synthetic pitch in accordance with FIFA (2008) laws. Judo Results: Results indicate that experts group differed significantly from near expert for fixations duration, and number of fixations per trial. The expert judokas used a less exhaustive search strategy involving fewer fixations of longer duration than their novice counterparts and focused on central regions of the body. The results showed that in defence and attack situation expert group did a greater number of transitions with respect to their novice counterpart. Soccer Results: We found significant main effect for the number of locations fixated across outcome (goal/save) but not for foot contact (instep/inside). Participants spent more time fixating the areas in instep than inside kick and in goal than in save situation. Mean and standard error in search strategy as a result of foot contact and outcome indicate that the most gaze behaviour start and finish on ball interest areas. Conclusions: Expert goalkeepers tend to spend more time in inside-save than instep-save penalty, differences that was opposite in scored penalty kick. Judo results show that differences in visual behaviour related to the level of expertise appear mainly when the test presentation is continuous, last for a relatively long period of time and present a high level of uncertainty with regard to the chronology and the nature of events. Expert judoist performers “anchor” the fovea on central regions of the scene (lapel and face) while using peripheral vision to monitor opponents’ limb movements. The differences between judo and soccer gaze strategies are discussed on the light of physiological and neuropsychological differences between near and far space perception.