Question

What changes can be observed in the length of A band during muscle contraction?

Answer 1

• According to the sliding filament theory, the actin(Thin) and myosin(thick) filaments within the sarcomeres of muscle fibres bind to create cross-bridges and slide past one another, creating a contraction.
  
• Upon muscle contraction, the A-bands do not change their length i.e the length of A band remains constant. whereas the I-bands and the H-zone shorten. This causes the Z lines to come closer together.