Characteristics of throwing arm movement for an elongated implement: a comparison of the javelin and baseball throwing.

BACKGROUND: In javelin, although many previous studies have examined throwing movements that can increase initial velocity, the characteristics of throwing arm movement an elongated implement have not been clarified. The purpose of the present study was to examine the characteristics of the throwing movement of an elongated implement by comparing throwing movement between a javelin and baseball. METHODS: Twelve male javelin throwers were asked to perform a javelin throw (JT) and a baseball long toss (LT) twice. The three-dimensional coordinates of reflective markers attached to the athlete's body, javelin, and baseball were measured using an optical motion capture system. %Trajectory was used as an index to evaluate the degree to which the hand was moved linearly during the throw. A smaller value of this indicator meant that the hand was move closer to a straight line. The joint angles in the throwing arm were obtained by calculating the Euler angles between body segments. These data were used to compare JT and LT. RESULTS: %Trajectory showed that JT was significantly smaller than LT. Significant differences in the joint angles of the throwing arm were noted between JT and LT. CONCLUSIONS: JT showed a kinematic pattern in which the hand was moved more linearly than in baseball long toss.

Kinematic Contribution to Javelin Velocity at Different Run-Up Velocities in Male Athletes.

In javelin training, many athletes improve their throwing technique by throwing from a slower run-up velocity than in competitions. However, whether the acquisition of javelin velocity in throwing from a slower run-up velocity is the same as in full run-up throwing is unclear. The purpose of this study was to clarify the differences in the contribution of each movement to the javelin velocity caused by changes in the run-up velocity within an individual. Twelve collegiate male javelin throwers were included in this study. Athletes performed two types of throws: one-cross throwing (Cross) and full run-up throwing (Run). The coordinates of reflective markers attached to the thrower's body and the javelin were recorded using an optical motion capture system. The percentage contribution of each joint movement to the javelin velocity was calculated and compared between Cross and Run. Cross had a lower contribution of trunk forward lean to forward and upward javelin velocities compared to Run. On the other hand, Cross had a higher contribution of trunk counter-clockwise rotation to forward and upward javelin velocities than Run. These results suggest that as the velocity of run-up changes within an individual, the acquisition of javelin velocity also changes.