I have been reading and posting a lot over the years on a few forums strictly dealing with javelin technique and let me tell you there are lots of different methods and techniques discussed. I have always like to keep things real simple but others can discuss pages worth of information just dealing with the angle of the arm or neck compared with the the foot and ankle. :)
Here is how I see things regarding throwing the javelin very far. It has to do with how sudden you stop. That's it in a nut shell for me and I have had good success coaching throwers on how to stop.
A lot of coaches do see your type of mechanics in the throw and use a term called "elastic reflex" in discussing this spring effect. Right or wrong I don't follow along with them because I see so much is missed when not discussing the huge reactionary force you can create immediately by stopping.
And let me now try to be convincing in discussing my rather absurd remark of how a little, slow, weak thrower can beat a big, fast, strong thrower. If this sport relied on springs or the more common javelin coaching term called levers, throwers with longer levers, basically your big guys would win or throw father on average. The fact is they don't. I am not a physics major so please correct me when I get something wrong in that field but I believe it takes less force to stop something moving the same speed that is smaller in mass. What I am trying to say is that little throwers stop quicker.
Second point is dealing with speed of the thrower but with the same principal in mind, the faster you go, the more force it takes to stop you. So throwers that move faster, can't stop as easy as slower ones, resulting in loss of force they would get in a sudden stop reaction.
Third point strength. I could go on and on with stories of javelin throwers setting records while in a weaken state, coming off illness, lack of sleep, etc. I have discussed before the importance of relaxing you arm and not trying to time the throw. If a thrower acts on a throw instead of reacts, normally the throw goes nowhere. There are tons of big arm throwers that place last. A lot of coaches picture the javelin throw like a whip type of action and a whip is quite thick and strong at the base but quite thin and weak on the opposite end. If the end of the whip was the same as the base, I am sure the snap wouldn't be as loud or fast at the end. Being weak in your throwing arm has big advantages in this event.
So those are my points on my absurd statement. :)
Now with the premise of being it's all about stopping, how do you do that efficiently? How do you not lose your momentum before you stop? A good majority of throwers lose a great deal of momentum on the second to last step. When you notice Uwe throw above, take note of his right knee at the time he lands his right foot. It is colasping. It may look like a normal bend but he is moving at a good deal of speed, so keep that in mind. If he didn't "soft step" that right leg, he would never get that plant leg down at a good angle to stop his moment and his momentum would be slowed before he is able to stop. In the way I see things you want to carry as much speed as you can into the plant leg and if your plant knee doesn't buckle you going to create a huge amount of reactionary force.
Last thing is on the bend of the knee on the plant leg. There are some very good coaches who think this isn't a big deal and some who suggest you should try to emulate a bend in the plant knee. In my style of throwing/coaching, a millimeter bend in the knee is a horrible loss of a lot of reactionary force. I think of this loss the opposite way seat belt manufactures think of making seat belts. The design them so they slow you momentum down, real quickly of course but they definitely don't design them to stop you suddenly. That would be way to much force on your body to take so they design a certain give to them. In javelin throwing you don't want any give because you look to gain as much reactionary force which comes with this jolting sudden stop.
Thanks for reading my thoughts of this event Fu-Kwun.