THROWS
Summations of Force Upper body activity in delivery and the strike should result from a summation of forces. The large muscle groups of the body’s core initiate the movement. Joints subsequently contribute to force generation and application, progressing from the body’s core outward. While each throw has a unique ideal firing order, proximal to distal firing must be preserved. This proximal to distal firing relationship is also observed in the rotational aspects of delivery, as the body’s core turns first, while the upper body temporarily remains passive. During delivery, the body must turn smoothly in the direction of the throw. However, the upper and lower bodies do not turn from the same positions at the same time. In the delivery position, the shoulders are rotated farther from the direction of the throw than the hips. This relationship of the hips and shoulders is called separation, referring to the separation of their respective axes. Separation 20
techniques NOVEMBER 2017
is present as the delivery position is achieved in all throws, but the specific positions of then hip axis, shoulder axis, and degrees of separation vary. In efficient throwing, during delivery, unique patterns of extension exist between the upper and lower bodies. The hip joint should extend in concert with the hip, the knee with the shoulder, the ankle with the wrist, etc. This has great implications for the rotation necessary in good throwing, since excessive and/or premature extension in the upper body will disrupt rotation and promote extension in the lower body, and vice versa.
Elastic Energy Generation The sweep of the non-throwing arm, coupled with the block, serves to set up an elastic situation in the chest musculature that helps accelerate the implement. There is a slight amount of flexion in the legs that occurs in response to the impact associated with landing in the delivery position. This will set up an elas-
tic situation as the legs extend, applying vertical force to the implement. The delivery phase of the throw should be initiated with a turning of the lower body, while the upper body remains passive. This creates a twisting of the core of the body called torque. This torque creates the potential for elastic energy generation as untwisting occurs, and serves as the mechanism by which rotational energy from the lower body is transferred to the upper body. In the throws, when we examine the path of the body’s center of mass through the approach and delivery phases, we see vertical rises and falls. These provide opportunities for elastic loading via joint flexion and extension and potential energy development. An oscillating system is created requiring less energy input for high performance. When we examine the path of the implement through the approach and delivery phases, we also see vertical rises and falls. Again, these provide opportuniIMAGE OF SPORT PHOTO