The Biomechanics of Elite Javelin Throwing Technique
AbstractThe aim of the study was to contribute to understanding of elite javelin throwing techniques, m particular, to establish relationships between the athletes' movement patterns and the distances thrown. Every throw of all twelve throwers in the men's javelin final at the 1994 European Championships was filmed using a NAC high speed video camera (200 Hz) situated perpendicular to the javelin runway and a Magnavox camcorder (60 Hz) placed to the rear of the runway. Manual digitisation techniques were used to generate 2-D image space coordinates and direct linear transformation methods were used to reconstruct 3-D real-world coordinates. The digitised 200 Hz sequence was interpolated prior to 3-D reconstruction to represent a 60 Hz sequence. Event synchronisation was achieved by observing athlete's foot strikes. Initial results showed many similarities between the throwing techniques used by the 12 athletes. Run-up speeds at final foot strike (FFS) were calculated to range from 5.6 as" to 6.6 ms" for nine of the 12 athletes studied, and the carry height of the javelin, m relation to the height of the throwing shoulder at FFS ranged from +1 cm to -9 cm. With respect to the kinetic energy transfer between body segments, it was found for all athletes that the peak kinetic energy for the lower body occurred first, followed by the trunk, upper arm, lower arm, then javelin. Marked differences m throwing technique also occurred between throwers. For example, for the three medal placed throws the centre of mass speed at FFS was reduced by over 40 % prior to that at release (only two other throwers achieved comparable levels). This enabled these throwers to release the javelin from a unique position (with one exception) inside of two metres from the foul line. Furthermore, they were the only athletes to achieve peak wrist joint centre speeds of wer 20 as-' relative to their centre of mass speed. This was significantly related to the reduction in nm-up speed during the delivery (r = 0.60, p = 0.039) and suggested transfer of momentum from the lower body to the upper body and javelin. In conclusion, certain fundamental characteristics of throwing technique were common to all throwers and would be applicable for coaching to athletes of all levels. In contrast, differences in throwing styles (e.g. large differences in angular velocities of the upper and lower arms) would suggest different training requirements for optimising performance and protecting against injury.
Coaching and Sports Activities
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