Force summation

Feedback Cue:

• Take note of how the athlete stands before throwing, the aim is to start side on and begin with rotating the body ending with the use of the arm.

Figure 3: The Principle of Force Summation, highlighting the importance of sequential timing. Image Courtesy of: http://www.coachr.org/biomechs5.jpg 

The weight change to the front foot allows power to be generated by the largest muscle group first, through the rotation of the body’s vertical axis. This is also known as angular velocity or put  simply ‘the rate of change in angle of the thrower.’ (Blazevich, 2013, p. 16)  To ensure optimal force summation the sequences of the movement need to be completed in order and correctly timed. The optimal technique as highlighted by Figure 3 involves the largest muscle groups first and then follows down the kinetic chain to the smaller muscle groups whilst the previous body part is still at its maximum speed of movement. (Landlinger et. al, 2010) The greater the force generated the more angular velocity is generated by the rotation of the hips. The projectile and the angular velocity have a linear relationship thus the faster the angular velocity of the body, the faster the projectile will be moving. The angular velocity is. It is quite obvious that the more quickly the thrower rotates (that is, the higher their angular velocity), the faster the ball will be moving and thus meeting the goal of maximum ball velocity.