There is a relationship between the length of a muscle fiber and the tension of a muscle fiber. It is known that the shorter the muscle fiber, the less force they exert. This can be seen by a demonstration using your wrists and hands. If one flexed their hand downward so that the hand is perpendicular to the wrist, less force will be exerted when they try to grab another finger tightly with the hand in this position. However, with the hand normally extended, the hand can tightly grasp another finger with full force. This is due to the idea that muscles have an ‘optimal’ length. This optimal length is identified as the length that it most useful for exerting forces. The length of the muscle when in a normal position is optimal to allow the hand to grasp a small object, while the flexed position is not optimal. For example, if the thick and thin filaments in a sarcomere are further apart, there is a decreased number of motor proteins that can pull on the thin filaments to move inward. Therefore, the lower amount of touching motor proteins lowers the force that it able to be exerted on another object. This is also due the crossbridge cycle. The closer the thin and thick filaments are to eachother, the lower amount the muscle will be able to contract with the restriction of the crossbridge cycle.
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