2009 World Champion Primož Kozmus showing a solid hammer position.

An Introduction to Biomechanics

I recently came across a biomechanical analysis of the hammer throw at the 2009 World Championships in Berlin. While the report is brief, it perfectly illustrates a few points that all hammer throwers need to know.

2009 World Champion Primož Kozmus showing a solid hammer position.

Basic physics tells us that there are three main variables that impact the distance of the throw: (1) the velocity of the hammer at the time of release; (2) the angle of release; (3) and the height of release. Obviously other factors also come into play, such as the wind, the density of the air, and so on, but these factors are the same for everyone and cannot be influenced by the throw. The height of release also plays a relatively small role since it remains fairly constant despite attempts by Harold Connolly in his prime to try to throw will taller shoes.

This report, conducted by the German Olympic Training Center in Hessen, simply provides raw data and refrains from making any conclusions. By looking at high speed film, the team determined the speed of the hammer, the duration of each turn, the path of the hammer, and several other variables. This data teaches you a lot about the hammer without even looking at the throws (although looking at the throws is just as fun: you can view video Primož Kozmus’s winning throw here. Here are the most important conclusions you can draw from it:

  1. Of the three factors, the speed of the hammer matters the most. If you ranked the throwers by their hammer speed, you would end up with almost exactly the same ranking as the final results.
  2. The angle of release barely matters. This is something Kibwé Johnson pointed out after attending the USATF Throws Summit earlier this month. All things being equal, a steeper the angle of release is better. However, adding several degrees of orbit to the throw only contributed 10-20cm in distance for many throwers. The only time it played a role was when the two athletes had the same or close to the same hammer velocity; in that case the steeper orbit resulted in a better throw.
  3. Hammer speed does not equal body speed. Every thrower agrees that is the most important variable, but most are often thinking about body speed. Or they assume that a faster body speed means a faster hammer speed. They are not the same. You don’t have to accelerate the body to accelerate the hammer. Simply increasing the radius increases the hammer speed because the hammer has to go faster to keep up with the body. The two fastest throwers at the competition were Krisztián Pars and Markus Esser. They placed fourth and sixth respectively. While they were ranked at the top for speed, the ranked at the very bottom for radius (as measured by the distance traveled by the hammer during the throw; a longer radius meands a longer path traveled by the hammer). As a consequence, they were not able to fully transfer their speed into the hammer through a long radius. In looking at data from other competitions, Pars has thrown further while turning slower (for example, at the 2008 World Athletics Final). It comes as no surprise that Pars threw further at the World Athletics Final because he had a longer hammer path and thus a higher hammer velocity even though he was going slower.

This data is not revolutionary, but it does help illustrate the main focus of Dr. Bondarchuk’s coaching method: our focus is always on the speed of the hammer and not the speed of our body. It is easy to read the data, but much more difficult to put it into practice. Data only measures the effects of a throw, not the causes. Finding the cause is a long process that often involves counter-intuitive changes like slowing down to maintain radius and throw farther (as was seen in the Pars example). This transfer from theory to practice requires a coach, not just a biomechanist. Coaches can learn from experience what the cause might be. Many biomechanists lack this experience or background. Therefore it is often the best to take their data findings and use them as goals rather than relying on them for all technical matters as more and more biomechanists are advocating.

Click here to download the complete report.

3 replies
  1. Emil Muller
    Emil Muller says:

    Hi fellow hammer thrower,
    I am a hammer coach and thrower for many decades .Hall of famer in Canadian Masters athletic association.I like your letter .We are on the same wave length.For not too knowledgable people you should add at #2 that
    there is a limit of the angle of release of the implement , something around 43 degrees .After this the distance is getting shorter. I know you know this , but some people do not .
    Keep writing , it is always interesting. Cheers Emil Muller 75 and still throwing at international level.

    • Martin
      Martin says:

      Definitely, thanks for pointing that out. Steeper is not always better, but you rarely see throws steeper than 44 degrees anyways (then you start getting close to hitting the ground), so I didn’t think that was worth mentioning.


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