The Elbow and Radioulnar Joints
Almost and movement of the upper extremity will involve the elbow and radioulnar joints. The elbow joint is intimately associated with the radioulnar joint in that both bones of the radioulnar joint, the radius and the ulna, share an articulation with the humerus to for the elbow joint.
Pitching
Pitching is on of the most important things in the game of softball. The pitcher touches the ball in every play and can control the offensive game depending on her ability. The act of pitching requires the whole body, but manipulating the ball to spin the way you want requires the movement of your radioulnar joint. Below are 6 different pitches thrown by the same pitcher. Each pitch moves with a different spin because of the movement of the radioulnar joint at the release of the ball. It is very important that these movements are precise in order to get the exact spin needed on the ball. The difference between a strikeout and a home run lies in the movement of this joint.
Fastball
The fastball is the most basic pitch and the first one a pitcher learns. It is a very effective pitch up through high school, but at the college level it isn't. This ball is thrown at 4 different spots around the plate and requires very little change to place the ball in the spots. The ball is released at the hip to ensure the pitch is the right height. After the ball is released you follow through straight up. When I was taught to pitch the coach always suggested I pretend to "pick a penny" off of my shoulder when finishing the pitch. When in pitching motion the arm should be out-stretched and slightly bent at the elbow. Below is a couple of example of the arm in the different positions of pitching.
In a fast pitch the position of the thumb is rotated at different points of the circle. This is provided by rotation in the radioulnar joint. The first picture shows position one. You hands are thrown towards the catch and your lower body starts to open up in the line of power. In this position the right thumb (holding the ball) is point towards the glove hand. The radius is the bone on the thumb side of your arm and it is pointing in the upward direction where as the ulna (the bone on your pinky side) is pointing towards the ground. In this position the elbow joint is at a neutral angle.
The second picture is another position in the pitching movement. In this position the thumb is pointed towards the opposite wall; the radius is pointing in the direction of her other hand and the ulna is pointing away from her body. From this position the thumb is then turned downwards pointing towards the floor. In this position the radius is then pointing towards the back wall and the ulna is point in the same direction as her backside. Picture 2 shows an example of this. The rotation the arm goes throw is provided by the should and radioulnar joint.
Change up
Above is an example of the release of a change-up pitch. To throw the change-up, do so with the same arm speed as the fastball, flipping
your wrist and forearm before you reach your hip. The hand comes over the top and the shoulder and elbow cause the movement in this pitch. The follow through is very important in this pitch and others. The elbow joint is kept straight, but it is rotated until it is pointed upwards toward the ceiling. In the follow through the ulna would be pointed upwards towards the ceiling and the radius would be at a 45 degrees angle between the ground and wall. The release is also higher than the release of the fastball which is at the hip. Below is a professional pitcher throwing the same pitch. You can see the hand being moved into a prone position prior to the release of the ball. This movement internally rotates the glenohumeral joint and extends the elbow. It is the internal rotary movement of the radius on the
ulna that results in hand moving from palm-up to palm-down position.
Drop Ball
The drop ball is similar to the particular change-up Rachel, the pitcher above, throws in that the hand goes from pronation to supination. This pitch is mainly the product of the should. The hand rotates over the top of the ball into the prone position during follow through. Rolling the hand over the ball is what causes it to drop. The bicep brachii participates in the supination of the forearm. The Triceps Brachii also participates in this movement. If you notice in the picture Rachel's triceps are flexed which helps her flex her elbow joint and throw the pitch correctly. Strengthening the Triceps Brachii can be done by simply by doing push ups. Push ups demand strenuous contraction of this muscle. This muscle can also be stretched with the shoulder and elbow in max flexion; this is equivalent to the stretch we do where we reach behind our head and pull it even further with our free hand. Below is an example of a professional pitcher throwing a drop ball. It should be noted that if the arm is not kept close to the body it can result in an injury.
Rise Ball
The rise ball is said to be one of the hardest pitches to learn. It demands that the body be efficient and that the timing to be spot on. This pitch looks like the pitcher is snapping her finger on release and bring her elbow into flexion across the body. In this pitch the shoulder should be as open as possible during the release and you should feel like you are almost going to fall backwards. Ideally, the arm will finish with a short upward
follow-through toward the target, with the inside of the
elbow facing away from the body; 2nd &
3rd fingers will be bent pointing upward. The bicep brachii plays a big roll in this pitch. When releasing the ball the follow through puts the elbow into flexion. The bicep is commonly known as a three-joint muscle. It is most powerful in the flexion of the elbow when the radioulnar joint is supinated. If you notice the follow through of this pitch you will see that the hand is in supination. To stretch this muscle the elbow must be extended maximally with the shoulder in full extension. It can also be stretched by beginning with full elbow extension and progressing into horizontal abduction. In both cases the forearm should be fully pronated to achieve maximal lengthening of the biceps brachii.
Ulnar Collateral Ligament Injury
This injury is cause by side-arming the ball when throwing over-handed. Poor mechanics, lack of conditioning, flexibility and fatigue from overuse can all have the cumulative effect that leads to the decrease in active muscular protection of the medial elbow and hence greater stress to the ulnar collateral ligament. When the ligament is first injured inflammation and edema are present within the ligament. With continued stress to the ligament, dissociation of the ligament fibers occur, progressing to calcification and ossification. This continues to increase over time until the ligament finally ruptures. This is why it is good to have proper throwing mechanics. If you can diagnose this injury at its early stages it can be easily fixed by changing the way you throw. Attenuation of the ligament can lead to joint instability, which effects overall performance and can subject the elbow to further injury.