Describe the development of force through the process of the sliding-filament theory, including crossbridge cycling?

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In the skeletal muscles, there are alternating bands of thin filament fibers called actin.  Myosin serves as a "ratcheting" mechanism between the filaments of actin, causing a paddle-and-grab type of motion, allowing the actin fibers to shorten.  As the filaments shorten across one another, force is generated, which is transferred to the ends of the sarcomeres.  This force is not evenly distributed, so uneven tension may be noted in less-thin areas of the skeletal muscle in question.  It should also be noted that skeletal muscles work in pairs, when one skeletal muscle is contracting in this fashion, the partner skeltal muscle is relaxing, rebuilding energy for the next contraction.  Skeletal muscles may be trained to generate increasing amounts of force by using resistance training, where some type of resistance, such as weights, are used to develop more of these actin filaments along which the myosin may work its ratchet effect.

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how does the sliding filament mechanism develop force through the process of crossbridge cycling and excitation-contraction coupling?

Sliding filament mechanism is a theory devised in order to understand the motion of muscles during contraction and relaxation. As the muscles contract, the muscle fibers generate tension which is due to the action of a globular protein actin and the ATP dependent protein myosin in the cross bridging cycle. 

The result of cross bridging cycle is possible through the excitation-contraction coupling that allows the conversion of electrical impulses (in the form of action potential) into mechanical responses. These mechanical responses are the force that are produced and eventually movement or contraction. 

The force that was created is due to the complex biochemical reaction of combination of actin, myosin and ATP in order to produce energy (or force), ADP and an inorganic phosphate. 

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