Investigation of motion factors in female javelin throwers during success and failure trials

Abstract

The purpose of this study was to investigate motion factors in female javelin throwers during success and failure trials from a biomechanical standpoint. Fourteen throwers who participated in the Japanese Women's Javelin Championships Final were investigated during both success trials and failure trials and the results were compared. The success trial was set as the best record and the failure trial as the worst record. Timing points of throwing motion were set at right foot contact (R-on), left foot contact (L-on) and javelin release (REL). The main results were as follows; 1) There was no significant difference in approach velocity between the success and failure trials. 2) In the success trials, peak speeds of the right shoulder, elbow joint and javelin were higher than those in the failure trials. 3) In the success trials, the left rotation velocity of the shoulder angle was larger than that in the failure trials just after L-on. 4) In the success trials, the forward rotational velocity of the trunk was larger than that in the failure trials just after L-on. 5) In the success trials, the throwers maintained a more extended position of the left knee angle than in the failure trials between L-on and REL. These results revealed that superiority or inferiority for female javelin throwers at the same competition level was determined not by the approach velocity, but by the blocking motion of the left leg. Although the importance of this left leg blocking motion has been reported many times in previous studies of throwers with different performance levels, it has been shown here to play an important role in the success of individual performance.