Biomechanics: Shot Put, Discus Throw and Other Throws
The shot put, discus throw and other throwing events in track and field have several biomechanical applications that will have an influence on technique and throwing distance.
Release velocity, release angle and release height are the three major biomechanical factors related to throwing distance according to Introduction to Coaching: the Official IAAF Guide to Teaching Athletics (Thompson, 2009).
Release Speed, Angle and Height
According to a biomechanical report from World Athletics in the shot put, at the 2018 World Championships, Tom Walsh had the highest release velocity at 14.12 meters per second (m/s) with a release angle of 37.3 degrees at 2.11 meters (6’11”) high to win the competition. (Dinsdale, Bissas, & Merlino, 2019).
Release velocity is generated by the total force applied during the throwing technique that is transferred to the release of the implement. In most throwing events, the initial movements of the throw will contribute 20-30% of the final release velocity. Therefore, 75-90% of the release velocity is generated during the last phases of the throw.
In the shot put and discus throw, 75-90% of the release velocity will be generated after the front leg makes contact at the front of the circle. The throwing position at the front of the ring is called the power position. After the thrower lands in the power position, the majority of the force generated for release velocity will take place.
In the javelin throw, run up speed prior to the final two steps will also account for 20-30% of the release velocity speed, the remaining 70-80% of the release velocity will be once the front leg is planted similar to the shot put and discus throw.
The hammer throw involves a gradual build up in speed during the execution of the technique when compared to the other throwing events.
Release velocity is generated by time and distance of force applied to the implement; this is accomplished by accelerating the implement over a long path quickly. In addition, an active throwing side leg from the power position to release, a strong non-throwing side bracing action prior to the release and proper timing (summation of forces) generated into the release of the implement will have a positive influence on release velocity.
The release velocity of the implement will be the number one factor related to distance thrown. Release velocity is the speed of the implement when it leaves the hand. A small increase in release velocity will result in a much further throw in most cases.
Training to optimize speed and strength for the shot put and discus throw requires using the proper exercises that transfers to the event known as Transfer of Training.
The angle of release is another important factor in the throwing events. The optimal angle of release varies with each throwing event but is usually between 34-39 degrees. The optimal release angle will depend on what angle the thrower can get the most velocity. Elite throwers have different release angles in part because they generate force differently prior to the throw and how that force is translated into the implement at release. The physical attributes and technical execution of each thrower will have an impact on the release angle.
In the spin shot put, some throwers have an extremely narrow base at the front of the circle. This will create tremendous vertical lift at the finish resulting in a higher angle of release. The glide shot put has a wider base or power position, slightly wider than shoulder width. A wider base allows the thrower to drive the shot put out more creating a lower angle of release.
Optimal Release Angles
Shot Put: 35 to 41 degrees
Discus Throw: 39 degrees
Javelin Throw: 30 to 40 degrees
Hammer Throw: 42 to 43 degrees
The release height at delivery is the third key factor in determining release distance. Anthropometric factors, release point and body position during the delivery phase will influence the height of release.
In the discus throw, some throwers throw without reversing the feet while other throwers do lift off the ground reversing. The throwers not using the reverse have a reduced height of release but could increase release velocity because of the force being applied over a longer path to the implement with fixed feet.
Biomechanics: Body Mass and Throwing Distance as a Factor
In the article, Transfer of Mechanical Energy During the Shot Put, body mass and throwing distance in the glide shot put was researched concluding “a strong correlation was found in the group between personal best and body mass” (Błażkiewicz, Michalina et al, 2016).
Biomechanics: The Law of Conservation of Angular Momentum
The Law of Conservation of Angular Momentum states that a rotating system’s angular momentum remain constant unless acted upon by an outside force.
In the throwing events, keeping the block arm out long in the beginning of the power position slows down the upper body because the radius of the upper body is increased, allowing the lower body to apply force over a longer path. Just prior to the release, the thrower brings in the block arm close to the body decreasing the radius which results in more speed at the end of the throw.