A three-dimensional analysis of javelin throwing technique.
This paper reports a three-dimensional kinematic analysis of the best throws from the women's and men's javelin competitions at the 1991 World Student Games in Sheffield. This was undertaken to obtain accurate three-dimensional release parameter values for elite javelin throwers in a top competition, to relate the release parameters to important temporal and kinematic features of the javelin throwing technique and to carry out an assessment of the adequacy of two-dimensional estimates of release parameter values in comparison with those from the three-dimensional analysis. Cine-film was taken using two phase-locked Panasonic 1PL cameras running at a frame rate of 100 Hz, and every other frame was digitized. All methodologies were in accord with the guidelines of the British Association of Sports Sciences. The results indicated the possibility of two different throwing techniques, within and between individuals, relating both to the timing of hip joint actions within the kinematic chain and the trade-off between the impulse applied to the javelin and run-up speed. The results also indicated that important release parameter values assessed from the xz-plane alone differed only marginally from those from three dimensions. The extra information obtainable from three-dimensional analysis (such as angle of sideslip, incidence magnitude, azimuth angle, angle of track and yaw rate) along with the poor representation of the time-course of important variables obtained from the xz-plane makes the three-dimensional analysis of this event essential. This is further strengthened by the practical use of three-dimensional analysis in allowing coaches and throwers the opportunity to view the event from any perspective. Recommendations for future research include further three-dimensional kinematic analyses with priority being given to assessing ways of estimating wind conditions around the javelin runway and of incorporating the vibrations of the javelin within the analysis.