Current understanding about skeletal muscle contraction is based on the sliding filament theory proposed independently by A.
According to the sliding filament theory, during contraction the sets of thin filaments in each half of sarcomere are drawn toward the center of A band and subjected to sliding forces oriented in opposite directions[5-7] The sliding filament theory very well explained the shortening of skeletal muscle during contraction with reference to a single sarcomere with movement of Z discs toward center of that particular sarcomere.
The aim of this study is to review and analyze sliding filament theory in context of the movement of Z discs on either sides of A band during contraction of all sarcomeres in single muscle fiber.
To review and analyze the sliding filament theory, we have prepared a simulating model, which is explained with the help of figures in the later sections.
In our model, actin filaments can be manually slided over myosin filaments as is given in the sliding filament theory of muscle contraction and Z disc also move along with movement of actin filaments.
Then we have tried to slide actin filaments of two adjacent sarcomeres toward centers of respective sarcomeres as described in the sliding filament theory.
But when we tried to slide actin filaments in two adjacent sarcomeres toward centers of respective sarcomeres as it is described in the sliding filament theory, the Z disc that was common to both sarcomeres was not able to move toward the center of either sarcomere (Figure 2).
This observation was completely in accordance with the sliding filament theory of muscle contraction under consideration.
This finding was not in accordance with the sliding filament theory of muscle contraction.
Therefore, we tried to find out another possible mechanism in context of the sliding filament theory of muscle contraction.