The Biomechanics of the Field Hockey Drag Flick

The drag flick is important in field hockey as it gives a greater opportunity to score a goal at penalty corners than hitting does. However, there is a lack of scientific research conducted on this technique. The purpose of this research was therefore to undertake a technique analysis of the drag flick. Given the paucity of research 10 field hockey coaches were recruited to synthesise expert opinions using a consensus-based, modified three-stage Delphi poll, comprising initial interviews and subsequent questionnaires. 28 physical and technical attributes were agreed and informed the biomechanical analyses. The four corners of the goal were agreed as the preferential target areas along with ball accuracy as the overall performance criterion. Twelve mixed ability field hockey players (8 male and 4 female) (age 24.25 ± 4.83 years, height 1.75 ± 0.09 m and mass 77.29 ± 17.44 kg) were then recruited to perform 60 drag flick trials at a 1 m2 target positioned in a standard field hockey goal at a distance of 14.63 m. The trials were split into three conditions: Self-selected target area, performance criterion ball accuracy; self-selected target area, ball velocity; and prescribed target area, ball accuracy. Three-dimensional kinematic data was recorded from a motion analysis system using a 15-segment model to compute performance and technique variables. An analysis of the full time series of kinematic data was completed to determine the core movement strategy of the drag flick technique. The main findings showed that the task constraint of accuracy altered the kinematic sequencing of players from a throw like pattern to more of a push like pattern. The left and right hip and shoulder ab-/adduction and left and right elbow and wrist flex/-extension are the key joint angles which contribute to the core of the drag flick technique. A dimensional reduction technique (PCA) was then applied to the same data to decompose the complex, but highly redundant set of postures into a comprehensible number of uncorrelated variables. Each of these variables represented multisegmented movements, which could be visualized. The main findings were that the left and right flex-/extension of the wrists are key to drag flick technique, in addition to the lowering of the thorax. Also the lower body kinematics explain greater variance compared with the shoulder and elbow joints, as they dominate the principal components, accounting for most of the variance. Although further work is required, this research has enhanced the understanding of the technique of the field hockey drag flick, particularly with respect to the core movement strategy.