Lucy Parrington

Did you see that? Dissociating advanced visual information and ball flight constrains perception and action processes during one-handed catching

The integration of separate, yet complimentary, cortical pathways appears to play a role in visual perception and action when intercepting objects. The ventral system is responsible for object recognition and identification, while the dorsal system facilitates continuous regulation of action. This dual-system model implies that empirically manipulating different visual information sources during performance of an interceptive action might lead to the emergence of distinct gaze and movement pattern profiles. To test this idea, we recorded hand kinematics and eye movements of participants as they attempted to catch balls projected from a novel apparatus that synchronised or de-synchronised accompanying video images of a throwing action and ball trajectory. Results revealed that ball catching performance was less successful when patterns of hand movements and gaze behaviours were constrained by the absence of advanced perceptual information from the throwers actions. Under these task constraints, participants began tracking the ball later, followed less of its trajectory, and adapted their actions by initiating movements later and moving the hand faster. There were no performance differences when the throwing action image and ball speed were synchronised or de-synchronised since hand movements were closely linked to information from ball trajectory. Results are interpreted relative to the two-visual system hypothesis, demonstrating that accurate interception requires integration of advanced visual information from kinematics of the throwing action and from ball flight trajectory.

Game-based analysis of handballing in Australian Football

Handballing is the most efficient passing skill in Australian football with an 80% success rate. Other than the number and outcome of handballs, there is no game-based information available on handball quality. The aims of this study were to profile handball performance and to assess within-game factors associated with effective handballing. Handballs (N = 1140) from 14 Australian Football League games were coded for outcome, technical, decision-making and game-environment factors. Technically it was found that that most handballs during games were characterized by a stationary and square stance, and executed forward over a short distance. Decision-making components included passing under low pressure, within one and three s and with one to two passing options available. Under game-environment, handballs were predominantly made in the midfield and after the ball was caught in the air, with an ‘easy-receive’ lead-up. Efficiency was higher when the player was square, passed forward, and had a ‘knees-bent’ or running stance. Handballing efficiency was lower under increased pressure, when there were fewer passing options, in the attacking region of the ground, and after awkwardly receiving the ball before passing. These findings can help guide handball technical analyses and coaching programs.

Kinematics of preferred and non-preferred handballing in Australian football

Abstract In Australian football (AF), handballing proficiently with both the preferred and non-preferred arm is important at elite levels; yet, little information is available for handballing on the non-preferred arm. This study compared preferred and non-preferred arm handballing techniques. Optotrak Certus (100 Hz) collected three-dimensional data for 19 elite AF players performing handballs with the preferred and non-preferred arms. Position data, range of motion (ROM), and linear and angular velocities were collected and compared between preferred and non-preferred arms using dependent t-tests. The preferred arm exhibited significantly greater forearm and humerus ROM and angular velocity and significantly greater shoulder angular velocity at ball contact compared to the non-preferred arm. In addition, the preferred arm produced a significantly greater range of lateral bend and maximum lower-trunk speed, maximum strike-side hip speed and hand speed at ball contact than the non-preferred arm. The non-preferred arm exhibited a significantly greater shoulder angle and lower- and upper-trunk orientation angle, but significantly lower support-elbow angle, trunk ROM, and trunk rotation velocity compared to the preferred arm. Reduced ROM and angular velocities found in non-preferred arm handballs indicates a reduction in the degrees of freedom and a less developed skill. Findings have implication for development of handballing on the non-preferred arm.

Biomechanical characteristics of handballing maximally in Australian football

The handball pass is influential in Australian football, and achieving higher ball speeds in flight is an advantage in increasing distance and reducing the chance of interceptions. The purpose of this study was to provide descriptive kinematic data and identify key technical aspects of maximal handball performance. Three-dimensional full body kinematic data from 19 professional Australian football players performing handball pass for maximal speed were collected, and the hand speed at ball contact was used to determine performance. Sixty-four kinematic parameters initially obtained were reduced to 15, and then grouped into like components through a two-stage supervised principal components analysis procedure. These components were then entered into a multiple regression analysis, which indicated that greater hand speed was associated with greater shoulder angular velocity and separation angle between the shoulders and pelvis at ball contact, as well as an earlier time of maximum upper-trunk rotation velocity. These data suggested that in order to increase the speed of the handball pass in Australian football, strategies like increased shoulder angular velocity, increased separation angle at ball contact, and earlier achievement of upper-trunk rotation speed might be beneficial.

Kinematic effects of a short-term fatigue protocol on punt-kicking performance

Abstract The punt kick is a fundamental skill used in several team sports; however, there has been a lack of research on how fatigue affects its technique. The purpose of this study was to determine the effects of short-term fatigue on punt-kicking performance. Eight elite and sub-elite Australian Football players performed maximal drop punt kicks on their preferred leg prior to, during and after a match-specific fatigue protocol. Optotrak Certus collected kinematic data from kick foot toe-off until ball contact. Repeated-measures analysis of variance showed a significant increase in 20 m sprint times after each short-term protocol, indicating fatigue. Foot speed did not significantly change with fatigue; however, increases in the range of motion at the pelvis and kicking thigh, along with increases in kicking thigh angular velocity, occurred. For the support leg, maximum knee flexion angular velocity increased while there was greater flexion found at the knee and hip, and greater range of motion at the knee. Players are able to make kinematic adaptations in order to maintain foot speed while punting for maximal distance after short-term efforts.

Kinematics of a striking task: accuracy and speed–accuracy considerations

Abstract Handballing in Australian football (AF) is the most efficient passing method, yet little research exists examining technical factors associated with accuracy. This study had three aims: (a) To explore the kinematic differences between accurate and inaccurate handballers, (b) to compare within-individual successful (hit target) and unsuccessful (missed target) handballs and (c) to assess handballing when both accuracy and speed of ball-travel were combined using a novel approach utilising canonical correlation analysis. Three-dimensional data were collected on 18 elite AF players who performed handballs towards a target. More accurate handballers exhibited a significantly straighter hand-path, slower elbow angular velocity and smaller elbow range of motion (ROM) compared to the inaccurate group. Successful handballs displayed significantly larger trunk ROM, maximum trunk rotation velocity and step-angle and smaller elbow ROM in comparison to the unsuccessful handballs. The canonical model explained 73% of variance shared between the variable sets, with a significant relationship found between hand-path, elbow ROM and maximum elbow angular velocity (predictors) and hand-speed and accuracy (dependant variables). Interestingly, not all parameters were the same across each of the analyses, with technical differences between inaccurate and accurate handballers different from those between successful and unsuccessful handballs in the within-individual analysis.