Effect of Ball Drag Characteristics on Drag Flick Shot Velocity

In field hockey, the drag flick is one of the most important offensive movements, accounting for 30 - 50% of goals scored. Research on the drag flick shot technique is limited, with some focus on the ball release velocity, but little on the ball movement prior to release. PURPOSE: The purpose of this study was to determine the effects of ball drag characteristics on shot velocity. METHODS: Six right-handed players from the United States Men’s National Field Hockey Team performed drag flick shots aiming towards their preferred and the opposite corner of the net. Three reflective markers were affixed to each athlete’s field hockey stick and the ball was covered with reflective tape. Seven Vicon Vantage 5 cameras (120 Hz) and two Kistler force plates were used to collect stick and ball three-dimensional coordinates and ground reaction forces, respectively. Ball and stick data were used to determine the instant of ball pick up and release and force plate data was used to determine left foot touchdown (LTD). Ball path characteristics (length, time, average velocity) were computed for the early drag phase (ball pick up to LTD), late drag phase (LTD to release) and total drag phase. Ball path characteristic differences, as well as the relationship between these characteristics and release velocity were determined with t-tests and Pearson correlation coefficients, respectively (p < 0.05). RESULTS: The shape of the ball path for left and right shots were distinctly different and so a comparison of left and right shots was performed, without regard for athlete direction preference. Late phase ball drag distance and time were greater for left shots when compared to right shots (2.483 ± 0.487 vs. 2.310 ± 0.391 m, respectively; p=0.012 and 0.212 ± 0.043 vs. 0.197 ± 0.042 s, respectively; p=0.021). There were no differences in drag distance or time for the early phase or total phase and no differences in average drag velocity for any phase. There were significant relationships between release velocity and late phase drag distance (r = 0.509, p < 0.001), total drag distance (r = 0.503, p < 0.001), and late phase drag time (r = 0.374, p = 0.009). CONCLUSION: It appears that a longer drag path is advantageoius for generating ball velocity. This likely enables athletes to exert a greater linear impulse on the ball, leading to an increased velocity at release.