Perception of spin and the interception of curved football trajectories

Abstract

Using plain white and chequered footballs, we evaluated observers' sensitivity to rotation direction and the effects of ball texture on interceptive behaviour. Experiment 1 demonstrated that the maximal distance at which observers (n = 8) could perceive the direction of ball rotation decreased when rotation frequency increased from 5 to 11 Hz. Detection threshold distances were nevertheless always larger for the chequered (decreasing from 47 to 28 m) than for the white (decreasing from 15 to 11 m) ball. In Experiment 2, participants (n = 7) moved laterally along a goal line to intercept the two balls launched with or without ±4.3 Hz sidespin from a 30-m distance. The chequered ball gave rise to shorter movement initiation times when trajectories curved outward (±6 m arrival positions) or did not curve (±2 m arrival positions). Inward curving trajectories, arriving at the same ±2 m distances from the participants as the non-curving trajectories, evoked initial movements in the wrong direction for both ball types, but the amplitude and duration of these reversal movements were attenuated for the chequered ball. We conclude that the early detection of rotation permitted by the chequered ball allowed modulation of interception behaviour without changing its qualitative characteristics.

Visual strategies underpinning the development of visual–motor expertise when hitting a ball.

“…When compared to straight trajectories, a critical distinction required when intercepting curving trajectories is that the observer needs to account for a continuous lateral deviation in flight-path to predict the future location of the target. In other words, the instantaneous direction of the target is constantly changing, and therefore this must be taken into account in order to anticipate where the target will arrive (see also Bootsma, Ledouit, Casanova, & Zaal, 2016;Casanova, Borg, & Bootsma, 2015;Montagne, Laurent, Durey, & Bootsma, 1999;Peper, Bootsma, Mestre, & Bakker, 1994). This has led to the conclusion that the informational variables that would typically allow performers to accurately predict where a target will arrive may be less reliable when the target follows a curving trajectory, and therefore that there may be a fundamental limitation within the visual system that restricts the observer's ability to account for the continually changing trajectory of a curving target (Craig, Berton, Rao, Fernandez, & Bootsma, 2006;Craig, et al, 2009;Port, et al, 1997).…”

Interception in the presence of ball-swing: exploring the development of visual-motor expertise in cricket batting

“…That is, they continuously coupled the position of their body to the changing heading direction of the ball to ensure that their arrival location coincided with the arrival of the ball. This evidence of movement reversals (i.e., the ongoing alteration of position in space with continuing ball-flight information; see Casanova, Borg, & Bootsma, 2015;Craig et al, 2011;Montagne, Laurent, Durey, & Bootsma, 1999) suggests that performers are able to extract perceptual information from ball-flight as it unfolds to constantly modify the timing and coordination of their movement in an online manner (Peper et al, 1994). This may be slightly different in hitting tasks such as cricket batting however, as batters need to, at some point, predict the future arrival location of the ball because altering the batswing may be too difficult once the movement is initiated (see section 1.2.1; McLeod, 1987;Sarpeshkar & Mann, 2011).…”

“…When using predictive control, movements are planned on the basis of a prediction of the future location of the target (Tyldesley & Whiting, 1975); whereas when using prospective control, the movement is continuously modified on the basis of updated perceptual information as the task unfolds (Bootsma & van Wieringen, 1990). For example when examining the influence of swinging flight-paths on the movements of volleyball players, Lenoir et al (2005) found that the players continuously coupled the position of their body with the changing heading direction of the ball to ensure that their position coincided with the ball at the moment of arrival (also see Casanova et al, 2015). The heading direction (or bearing angle) refers to the angle subtended at the performer by the current position of the ball and the current direction of displacement (Chardenon, Montagne, Laurent, & Bootsma, 2004;Chohan, Verheul, Van Kampen, Wind, & Savelsbergh, 2008).…”

“…This imbalance in pressure generates an additional force acting perpendicular to the object's flight-path, causing it to deviate in the direction of lower pressure (i.e., the Magnus effect; see section 1.3.1; Mehta, 1985;Walker, 1999). Although much is known about how a ball swings, surprisingly little is known about how performers might account for the continuous lateral deviation of the target in flight to facilitate successful interception (also see Casanova et al, 2015;Montagne et al, 1999;Peper et al, 1994). Craig et al (2011) recently found that recreational soccer goalkeepers attempting to stop balls in a virtual environment were significantly worse when intercepting curving balls compared to balls following straight trajectories (15 vs. 57% of all targets).…”

“…As a result, a critical distinction required when intercepting swinging targets, compared to a straight target, is that performers need to account for the continuous lateral deviation in flight-path when predicting the future location of the target. In other words, performers need to obtain perceptual information from ball-flight that allows them to prospectively guide the position of the end effector (e.g., hands or bat) on the basis of the changing heading direction of the target to ensure that their position coincides with the future arrival location of the target (also see Casanova et al, 2015;Montagne et al, 1999;Peper et al, 1994). This is clearly a challenging task.…”