I understand that if the athlete complete stop, all the energy can be pass to javelin to make it more effectively.

Could you upload some photos related to the event with your reply message?
So that I can know about the situation more clearly.
(Click additional Options) just below the message box, you will be able to upload files.
And provide me typical numbers: speed of athlete, initial speed of javelin (or distances )...
Can you give me some website which provides information related to your event?

The more information I can have, I should be able to create something better fit with what you want.