Biomechanical Concerns. When we examine upper body activity on the throwing events, we are concerned with six key realms. They are lengthening the rotational path of the implement, delaying the upper body movements, turning, maintaining positional relationships, the sweep/block, and the strike.
Lengthening the Rotational Path of the Implement
- Closed Shoulders. During the delivery, we wish to lengthen not only the linear path of the implement, but also the rotational path of the implement. For this reason, we begin the throw with the shoulders closed. Closed shoulders means that as delivery begins, the shoulders are directed away from the throwing direction. The degree to which the shoulders are closed varies from event to event. These closed positions provide a greater angle through which the shoulders may turn before reaching their final position, and thus a longer path of the implement and longer force application times.
- Separation. As the delivery begins, the shoulders and hips should both be closed and facing away from the throwing direction. However, the shoulders must be closed more than the hips. This difference in alignment between the hips and shoulders is called separation, the term derived from the separation between the hip and shoulder axes.
Delaying the Upper Body Movements
- Initially Passive Upper Body. During the early stage of delivery, the thrower’s upper body should remain closed and passive. This allows the lower body to operate first, with the upper body moving only later upon receipt of energy from the lower body.
- Torque. The throw is initiated by turning the lower body (the turning of the upper body lags behind). This turning of the lower body, combined with the passiveness of the upper body, creates a twisting of the core of the body called torque. This torque creates stretch reflexes in the torso musculature, enabling greater subsequent acceleration of the implement as the core unwinds. This is the method by which rotational energy of the lower body is fed to the upper body.
- Turning. In reaction to the torque produced, the chest should smoothly and progressively turn toward the throwing direction, stopping when directed toward the middle of the sector.
Maintaining Positional Relationships
- An Unbroken Unit. As the turning begins, the positional relationships between the implement and all body parts should be preserved. Think of the head, shoulders, throwing arm, and implement all turning and moving as an unbroken unit.
- Common Errors. It is a common error, as delivery begins, to see throwers turn the head toward the throwing direction while the shoulders, implement and arms lag behind. This results in deceleration of the implement at a critical time in the throw.
- Momentum Development and the Free Arm. A wide sweeping movement of the nonthrowing arm prior to the strike serves as a momentum development tool to enhance the strike. Long levers result in greater momentum development, so the arm must be in an extended position. Also momentum is unique to a plane of movement, so this arm sweep must be aligned with the implement’s angle of release. In short (for a right handed thrower) the left arm should pass where the right arm is to follow.
- The Free Arm Block. As the upper body turns and approaches the direction of the throw, the nonthrowing arm should be pulled in toward the torso, decelerating the rotation of the nonthrowing side and producing an acceleration of the throwing side. Once the arm sweep is complete, the free arm wrist moves toward the ribs to perform this blocking movement.
- Cautions Regarding the Block. This block should decelerate rotational movement, but permit linear movement to continue. As the chest rotation slows, the chest must continue to advance in the throwing direction. Also, in order to create forces in the correct direction, the block must occur out in front of the body. This is easy to evaluate by looking at the thrower from the throwing arm side. When the wrist reaches the ribs, the shoulders must still be a little closed (directed 30-40 degrees from the throwing direction). It is a common error to see the shoulders facing the throwing direction as the block completes, producing a useless accelerative force that is directed outside the throwing sector.
Training Resource: Complete Teaching Progressions for the Throwing Events
- The Grip. The grip is a critical part of the throw. Body parts communicate with each other through fascial connections, meaning that proper striking mechanics are impossible to achieve if the grip is not correct. A good coach is adamant and uncompromising when it comes to the proper grip.
- Delaying the Strike. We’ve discussed how the upper body should remain passive and allow the lower body to act first in order to transmit energy to the upper body. In the same way, the throwing arm should remain passive and allow the blocking and turning movements to advance significantly before striking. This results in stretch reflexes and elastic energy transmission from the torso to the throwing arm. The strike should be regarded nearly as an afterthought in the teaching process.
- Sequential Firing and the Strike. Upper body activity in delivery and the strike should result from a summation of forces. Weight transfer and turning of the torso initiate the movement, then the shoulder contributes, then the elbow, then the wrist, hand, etc. While each throw has a unique ideal firing order, proximal to distal firing must be preserved. This sequential firing is consistent with the previously discussed concepts of delaying the upper body and delaying the strike.
- The Head. In most cases, a backwards tilt of the head during the strike, lifting the chin, is used in the delivery to improve leverage. Poor head positions (particularly chin-down positions) during the strike are common, and fixing them are an easy way to get big performance improvements quickly.
Related article: Lower Body Mechanics in the Throws