Occlusion techniques to train visual research strategies in sport

In sport, efficient vision is essential as participants and objects move in rapid and complex trajectories. The way athletes continually move their eyes to focus on selected visual field areas has generated considerable interest in recent research. It has long been known that experts use perceptual strategies in visual research. A search strategy controls eye movements to allow the performer to make more efficient use of the time available for the visual field analysis. These practices can be used to encourage players to direct their attention to the movements and positions of the players without the ball, thus developing anticipation. Many techniques have been used to study anticipation cues in sport and can be primarily divided into laboratory research and field research. The typical laboratory paradigm involves using video to simulate the visual field that the performer has available during the actual action. The most popular techniques involve the video occlusion approach and the reaction time paradigm. Instead, in field research, there is a greater ecological emphasis on measuring performance using techniques such as high-speed video analysis and the use of liquid crystal occluding glasses. This study aims to summarise the state of the art of effects of these perceptual strategies to understand how and to what extent they affect the various domains. Articles derived from Google Scholar, PubMed and Scopus search engines and databases were reviewed. Keywords included viewing time, visual occlusion, sports vision training. Only the articles that met the inclusion criteria (relevance of the topic, visual occlusion techniques as a training tool) were selected for systematic review. Data quality and validity were assessed by examining the methodologies of each study and comparing studies of similar populations using the PRISMA method. Research suggests that experienced players using these perceptual strategies globally improve at predicting ball direction and making accurate predictions based on pre-contact anticipation cues. However, some critical issues emerge as obstructing the vision during the performance can cause subjects to rely on different sources of information than those they would typically use. Perhaps the advancement of the technology of these occlusion systems could allow solving these problems, becoming a promising investigative technique in sport.