The importance of perturbations in elite squash: An analysis of their ability to successfully predict rally outcome

This study investigated the presence of perturbations within elite squash through the analysis of critical incidents responsible for successful rally outcome. Thirty one matches from the men’s 2011 Australian Open Squash Championships were analysed via a customised Dartfish performance tagging template. The type of critical incident (perturbation, unforced error, unreturnable shot, let/stroke, and miss-hit) was identified relative to shot selection, player/ball landing position and shot accuracy. Logistic regression analysis assessed the strength of predicting the critical incident responsible for successful rally outcome from the identified predictor variables (shot selection, player/ball landing position, and shot accuracy) and whether certain shot types yielded significant contributions towards such outcomes. The results showed that perturbations were identified 238 times (10%), which was noticeably less frequent than the other critical incident categories; unreturnable shots (36%), unforced errors (31%) and let/strokes (23%). A miss-hit occurred once. The predictive abilities of the logistic regression model demonstrated that it was only effective at predicting the unreturnable shot in relation to the identified predictor variables (98.7%, 94.7, 91.4%, and 100% accurate, respectively). Both Actor and Opponent identified the same shots as having a significant contribution towards rally outcome; volley (p < .01), boast/volley boast (p < .01) and drop/volley drop (p < .01 and p < .05 respectively). It was concluded that whilst perturbations are evident in elite level squash, their importance is questionable as they fail to contribute significantly to the outcome of a rally relative to other critical incidents.