Before attempting to establish a full technique for either the shot put or discus throw, coaches have to teach the athletes how to set up in the proper power position and execute a stand throw.
Commonly known as the delivery phase, this is familiar part of the throw. Sport scientists claim that the delivery phase accounts for nearly 70% of the distance achieved in a full throw. It is thus essential for coaches and athletes to devote all the time needed to master the mechanics of the delivery.
Unfortunately, this doesn't happen in most American junior and senior high schools. Most novice coaches and athletes prefer to concentrate on the full technique.
I believe that it's tremendously wasteful to work on the whole before mastering the most important "part". With this in mind, I would like to present a technical discussion of the delivery phase along with a teaching progression that will help young athletes master it.
The three basic factors that determine how far an implement will travel are: (1) the optimization of the speed of the implementation at release, the angle of the release, and the height of the implement at release.
Biomechanist Tom Ecker states that a 10% increase in speed at the point of release will result in a 21% increase in distance, all other factors remaining constant (Jones 11). It helps to remember that the rate of speed is governed by the amount of force that can be applied through an effective range of motion into the proper direction of the throw.
Since the release takes place during the delivery phase, it is extremely important for the coach and athlete to understand how to exploit each of these factors, while remembering that proper execution depends largely on possessing a mechanically efficient and consistent technique.
The angle of release will largely depend on the other two factors. As the height or speed increases, the release angle will decrease. In theory, the optimal angle of release for the glide shot put is between 39 and 42 degrees, for the rotational shot put between 35 and 38 degrees, and for the discus throw somewhere between 37 and 39 degrees (Judge).
The height of the release has a much smaller effect on the distance than the speed and angle of the implement at release. The height effect on distance is determined by the size of the athlete and his/her body position at the point of release.
Several genetic limitations apply here, with size providing the overall advantage. But, regardless of size, each athlete must learn to transfer his/her bodyweight from the rear leg to the front leg to achieve the summation of forces that produces a high angle of release.
TEACHING PROGRESSION
(Note: For analytical purposes, we will assume the athlete is a right-handed male.)
The power position is marked by a three-stage teaching progression, beginning with the stance.
We want the athlete to set up with his feet approximately shoulder-width apart, with the left foot parallel to and facing in the same direction as the right foot, which is placed at a 90-degree to the ring. The left toe is aligned with the right instep.
The feet should remain stationary until the athlete pivots around and into the throw. Many mistakes are caused by the instability of stance. For instance, the athlete will often choose to shift his weight back onto the front (left) foot after assuming the power position by rotating it in toward the back of the right knee.
Another problem occurs when the athlete rotates his right foot from 90 degrees to 45 or even 0, with the toe pointing toward the back of the ring. These situations destroy the balance and timing within the delivery movement.
The second technique that must be taught is how to separate the upper and lower bodies. The athlete should be set up in the standing power position, then checked to see that the hips are open to the side of the ring and that the shoulders remain level and closed in a toqued position parallel to the rear or the ring [ILLUSTRATION FOR PHOTO 1 OMITTED].
The third, and final, technique to be taught is how to lower into a balanced power position. As the body weight is lowered onto the bent right leg, the left side should form a 45-degree angle. It is crucial to bend at the knee, not the waist, in order to maintain a good posture.
Another critical point is for the weight to be centered on the ball of the right foot, with the heel off the ground.
Mac Wilkins, 1976 Olympic Gold Medalist, suggests that this position be viewed as being "back, down, and around" with the implement at a position of maximum leverage away from the body. It is also important for the head to remain centered with the eyes focused back and off to the right [ILLUSTRATION FOR PHOTO 2 OMITTED].
DELIVERY MECHANICS
Once the athlete is accustomed to aligning into a proper power position, he is ready to facilitate the delivery phase, which features rotational, horizontal, and vertical movement.
This can be viewed as turning, shifting, and lifting during the stand throw, and involves an exchange of force between the upper and lower bodies, with each assuming periods of activity and passivity.
The delivery can be thought of as a lower-body dominant activity, in which the turning right side (or rear leg) provides rotational and horizontal force against the blocking left side (or front leg).
The delivery phase begins with the rotational movement. The right foot starts to pivot in order to push the hips in front of the shoulders/implement, as the weight transfers from the rear leg to the front leg.
This rotational movement is assisted by the right heel as it turns out and the right knee as it turns in. During this pivot, the left arm and right knee aid the balance simultaneously, maintaining the proper range of motion, separation, and balance. The left arm action can be described as a reach or extension in a slightly outward and upward direction.
The rotation follows the horizontal movement of the right knee and hip - a smooth transfer of momentum from the rear leg to the front, in which the right knee moves in and down as the thigh and hip begin to move around and up.
After the hip drive starts to peak, the blocking action of the left leg combined with the extension of the right create a lifting action of the hip level. With the shoulders and hips facing the direction of the throw, the left arm bends and drives in and back, creating a counterbalance to the throwing arm, along with acceleration.
It is at this juncture that the two events differ.
In the shot put, the throwing arm pushes at the last instant, as a result of the leg and hip action. The elbow is up and drives into the shot through the same line as the hand.
The athlete must keep an eye on the elbow of his throwing arm in order to avoid prematurely pulling away with the head. An inside-out release with the thumb down will facilitate a vigorous wrist snap and punch with the throwing arm.
In the discus, the delivery motion is marked by a longer application of force. British national throws coach, Max Jones, likes to describe this action as a "sling," with the throwing arm coming through "fast and last."
The shoulder comes all the way around to a position in front of the body as the implement is released with the thumb down. Similar considerations need to be made in keeping the head centered.
In both events, the athlete has the option to reverse or not reverse his feet. Since both styles continue to be used with consistent success, we may assume that style is largely a matter of individual preference.
In the non-reverse technique, the athlete's feet stay planted after the implement is delivered. In the reverse technique, the right leg may shift to the front after release to brake the forward motion.
The feet should land 90 degrees away from the throw, with the left leg straightening out toward the rest of the ring to help maintain balance.
Next month: a teaching progression for the delivery.
