Muscular Analysis of Upper Extremity Exercises
Proper functioning of the upper extremities is critical for most sports activities, as we as for many activities of daily living. Strength and endurance in this part of the human body are essential for improved appearance and posture, as well as for more efficient skill performance. Specific exercises and activities to condition this area should be intelligently selected by becoming thoroughly familiar with the muscles involved.
Analysis of MovementWhen analyzing various exercises it is important to break down all of the movements into phases. The number of phases depends on the skill being used. For example, batting has a completely different number of phases than pitching does, but they do have something in common. They both have at least a preparatory phase, a movement phase and a follow-through phase. First is the stance phase. This phase allows athletes to assume a comfortable and appropriately balanced position from which to initiate the skill. Second is the preparatory phase, which is often referred to as the wind-up stage. It is used to lengthen the appropriate muscles so that they will be in a position to generate more force and momentum as they concentrically contract in the next phase. This is the most important phase and becomes more important as the need for explosiveness increases. The movement phase, sometimes known as the acceleration, action, motion, or contact phase, is the action part of the skill. The follow-through phase begins immediately after the climax of the movement phase, in order to bring about negative acceleration of the involved limb or body segment. This phase is often known as the deceleration phase and the decrease in velocity is usually attributed to high eccentric activity in muscles that were antagonists to the muscles in the movement phase. The last phase is the recovery phase. It is used after the follow-through to regain balance and positioning to be ready for the next sport demand.
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Stance
These are some examples of the stance phase. In the first picture the stance is that of a pitcher. The feet are on the mound about shoulder width apart and the hand are brought together in front of the body within the glove. The second pitcher is the stance of a catcher. This is the position the catcher takes in order to catch a ball thrown by the pitcher. The player is squatted on the balls of her feet which are shoulder width apart. The glove hand is extended in front of the body ready to catch the ball and the back hand is behind the back being protected from injury. In the last picture the batter stance position is shown. The feet are spread shoulder width with about 80% of the weight of the back leg. The bat is held by both hands that are placed close to the ear.
Preparatory
These pictures are examples of the preparatory stages used in softball. The first picture is of a batter in the preparatory stage. The muscles tense and the grip on the bat is increased waiting for the ball to be pitched. In the following photograph it shows the cocking stage before the ball is thrown. The ball is brought behind the body and above the head in order to be a position that would provide an accurate throw.
Movement
In the first two pictures an example of the movement of a batter is shown. The bat starts above the head and goes straight to ball. The faster this movement is the harder the ball is hit. In the third picture is an example of the movement of a pitcher in her wind-up. The larger the circle and the faster the centripetal force in the movement the faster the ball will go.
Follow Through
In softball the follow through is used to provide accurate throwing and harder hitting. In the first two pictures the batters are in their follow-through. By following through the ball after contact the ball goes farther. In the last picture the pitcher is in follow-through. This is an important skill in over-hand throwing as well as pitching. The follow-through helps you control where the ball is going. In pitching the follow also affects the spin as well as the path of the ball. This is probably one of the more important phases in softball.
Recovery
In the first picture the ball was just hit and the bat and hands followed through to their end position. Next , the recovery stage is when the bat is dropped and the runner gets in a position to start their next action which is running to first base. The second picture is that of a base runner taking a lead-off. In the recovery phase of this skill the runner gets in a balanced position before she has to either dive/run back to first base or steal second base. Either way she must recover into a position in order to start her next action.
Open Kinetic Chain
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In the body, an extremity can be seen as representing an open kinetic chain if the distal end of the extremity is not fixed to a relatively stable surface. In this case the "distal end of the extremity" is the hands. They are attached to a weighted ball that is moved up and over the head. This allows for isolation of a joint or muscle from the rest of the body. Most of weight lifting exercises are open chained. This is why we have to do many lifts to strengthen the whole body. For example, we have to to triceps extensions and bicep curls to strengthen the arm. This is two different exercises for one part of the body. In a closed kinetic chain activity we will see that it is not necessary to do multiple exercises to strengthen one part of the body.
Closed Kinetic Chain
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If the distal end of the extremity is fixed like in the example picture, the extremity represents a closed kinetic chain. In this closed system, movement of one joint cannot occur without causing predictable movements of the other joints in the extremity. Closed-chain activities are very functional and involve the body moving in relation to the relatively fixed distal segment. The advantage of this kind of exercise is that you can work more than one joint and group of muscles with one exercise. In the end, the joint is more stable due to the joint compressive forces from weight bearing.
SAID Principle
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The SAID principle stands for Specific Adaptations to Imposed Demands. This principle should be considered in all aspects of physiology conditioning and training. The principle, which states that the body will gradually, over time, adapt very specifically to the various stresses and overloads to which it is subjected, is applicable in every form of muscle training, as well as to other systems of the body. This is the whole reasoning behind strength training in the pre-season. The team lifts weights in order to create endurance and strength that could then be used during the season to help our physical ability to play.