The Effect of the Trajectory of Javelin Thrower's Upper Limb on the Muscles, Ligaments, and Reaction Forces at Elbow Joint

Our understanding of athletic and sports injuries, and sports medicine has grown immensely as we have become more aware of the importance of exercise and team sports. With the increased number of sports and games played, the risk of injury and the number of people affected have increased. Athletic injuries can occur when an individual is careless, or not fit enough to undertake sports and games. In some cases people become injured during the use of sports equipment. Athletic injuries result from over stress put on bones or muscles. Most common injuries are soft tissue; muscles, tendons, and ligaments injuries. Also, a dislocation occurs when two bones are jolted apart at a joint and is often accompanied by a ligament tear in the joint. In this study, a three-dimensional dynamic model analysis of the human elbow joint during javelin throw has been developed. The model was used to compare between the muscle, ligament, and reaction forces at the human elbow region of two athletes; a professional one and a beginner. The effect of the trajectory of the thrower's upper limb on the distance and on the muscles forces, ligaments forces, and reaction forces was investigated. The javelin throw distance recorded for the professional subject was as twice as that recorded for the beginner subject. The model results showed that the professional subject mainly depended on the upper limb major muscles to achieve his longer throw, while the beginner subject did not, mainly, depend on these muscles. In summary, identification of root causes, either in techniques or training programs, will minimize injury recurrences. The presented model may help in choosing the right techniques or training programs by which injuries, for human elbow joint, can be avoided or at least can be minimized.