Essay On Muscle Contraction

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The Correlation between Eccentric Strength and Agility in Male Field Sport Athletes.

There are three types of muscle contraction, isotonic, isometric and isokinetic. There are two isotonic contractions, concentric and eccentric. A concentric contraction is a shortening of the muscle fibres, an example of this being a bicep curl causing a concentric contraction on the biceps brachii causing the elbow to flex. An eccentric contraction is the opposite of this. During an eccentric contraction as the muscle contracts the muscle fibres lengthen. An eccentric contraction is important in deceleration where the quadriceps lengthen to slow down the limb. This type of contraction should transfer into agility as athletes with greater eccentric strength …show more content…

Agility has been described as “a rapid whole body movement with change of velocity or direction in response to a stimulus”. (Sheppard et al, 2006) This description identifies the inclusion of cognitive skills in determining agility. This definition applies to open skills only. Open skills cannot be pre-planned, however closed skills, such as sprinting or previously planned changes of direction, can be planned in advance. This is very important in every field sport as the ability to react quickly and allow the movements to match these reactions enhances performance. Many field sports require straight line running speed but more often than not fast change of direction is a defining factor of an athlete’s performance. Fast change of direction speed and ability to make the right decision in a game situation makes for an excellent athlete.
Many tests have been designed to test for change of direction speed. The 5-0-5 test is a timed agility test using rapid 180 degree turns and straight line speed. The Illinois test is a timed agility test using straight line speed and many multi directional changes. The Zig-zag test is a good indication of multiple directional changes. It is a timed test where the athlete must round cones set out in a figure 8.
Subjects used in this study were 10 male soccer players. The agility test that was chosen to best simulate this sport was the 5-0-5 agility test. This was due to the quick, snappy change

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